Index: uspace/lib/ui/src/paint.c
===================================================================
--- uspace/lib/ui/src/paint.c	(revision 86fff9712bf6c2a6891033ebd6d851fba27dd6ca)
+++ uspace/lib/ui/src/paint.c	(revision ad698f41375f8829d61f961fec3adf3cf7931200)
@@ -529,4 +529,78 @@
 }
 
+/** Paint maximize icon.
+ *
+ * @param resource UI resource
+ * @param pos Center position
+ * @param w Icon width
+ * @param h Icon height
+ * @return EOK on success or an error code
+ */
+errno_t ui_paint_maxicon(ui_resource_t *resource, gfx_coord2_t *pos,
+    gfx_coord_t w, gfx_coord_t h)
+{
+	gfx_rect_t rect;
+	errno_t rc;
+
+	rc = gfx_set_color(resource->gc, resource->btn_text_color);
+	if (rc != EOK)
+		return rc;
+
+	rect.p0.x = pos->x - w / 2;
+	rect.p0.y = pos->y - h / 2;
+	rect.p1.x = rect.p0.x + w;
+	rect.p1.y = rect.p0.y + h;
+	rc = gfx_fill_rect(resource->gc, &rect);
+	if (rc != EOK)
+		return rc;
+
+	rc = gfx_set_color(resource->gc, resource->btn_face_color);
+	if (rc != EOK)
+		return rc;
+
+	rect.p0.x += 1;
+	rect.p0.y += 2;
+	rect.p1.x -= 1;
+	rect.p1.y -= 1;
+	rc = gfx_fill_rect(resource->gc, &rect);
+	if (rc != EOK)
+		return rc;
+
+	return EOK;
+}
+
+/** Paint unmaximize icon.
+ *
+ * Unmaximize icon consists of two overlapping window icons.
+ *
+ * @param resource UI resource
+ * @param pos Center position
+ * @param w Window icon width
+ * @param h Window icon height
+ * @param dw Horizontal distance between window icon centers
+ * @param dh Vertical distance between window icon centers
+ * @return EOK on success or an error code
+ */
+errno_t ui_paint_unmaxicon(ui_resource_t *resource, gfx_coord2_t *pos,
+    gfx_coord_t w, gfx_coord_t h, gfx_coord_t dw, gfx_coord_t dh)
+{
+	gfx_coord2_t p;
+	errno_t rc;
+
+	p.x = pos->x + dw / 2;
+	p.y = pos->y - dh / 2;
+	rc = ui_paint_maxicon(resource, &p, w, h);
+	if (rc != EOK)
+		return rc;
+
+	p.x = pos->x - dw / 2;
+	p.y = pos->y + dh / 2;
+	rc = ui_paint_maxicon(resource, &p, w, h);
+	if (rc != EOK)
+		return rc;
+
+	return EOK;
+}
+
 /** Paint a text box.
  *
Index: uspace/lib/ui/src/wdecor.c
===================================================================
--- uspace/lib/ui/src/wdecor.c	(revision 86fff9712bf6c2a6891033ebd6d851fba27dd6ca)
+++ uspace/lib/ui/src/wdecor.c	(revision ad698f41375f8829d61f961fec3adf3cf7931200)
@@ -49,10 +49,22 @@
 #include "../private/wdecor.h"
 
-static void ui_wdecor_btn_clicked(ui_pbutton_t *, void *);
+static void ui_wdecor_btn_max_clicked(ui_pbutton_t *, void *);
+static errno_t ui_wdecor_btn_max_paint(ui_pbutton_t *, void *,
+    gfx_coord2_t *);
+
+static void ui_wdecor_btn_close_clicked(ui_pbutton_t *, void *);
 static errno_t ui_wdecor_btn_close_paint(ui_pbutton_t *, void *,
     gfx_coord2_t *);
 
+static ui_pbutton_cb_t ui_wdecor_btn_max_cb = {
+	.clicked = ui_wdecor_btn_max_clicked
+};
+
+static ui_pbutton_decor_ops_t ui_wdecor_btn_max_decor_ops = {
+	.paint = ui_wdecor_btn_max_paint
+};
+
 static ui_pbutton_cb_t ui_wdecor_btn_close_cb = {
-	.clicked = ui_wdecor_btn_clicked
+	.clicked = ui_wdecor_btn_close_clicked
 };
 
@@ -62,14 +74,36 @@
 
 enum {
+	/** Width of corner drag area */
 	wdecor_corner_w = 24,
+	/** Height of corner drag area */
 	wdecor_corner_h = 24,
+	/** Window resizing edge witdth */
 	wdecor_edge_w = 4,
+	/** Window resizing edge height */
 	wdecor_edge_h = 4,
+	/** Title bar height */
 	wdecor_tbar_h = 22,
+	/** Window width */
 	wdecor_frame_w = 4,
+	/** Window frame width in text mode */
 	wdecor_frame_w_text = 1,
+	/** Close button cross leg length */
 	wdecor_close_cross_n = 5,
+	/** Close button cross pen width */
 	wdecor_close_cross_w = 2,
-	wdecor_close_cross_h = 1
+	/** Close button cross pen height */
+	wdecor_close_cross_h = 1,
+	/** Maximize icon width */
+	wdecor_max_w = 10,
+	/** Maximize icon height */
+	wdecor_max_h = 10,
+	/** Unmaximize icon window width */
+	wdecor_unmax_w = 8,
+	/** Unmaximize icon window height */
+	wdecor_unmax_h = 8,
+	/** Unmaximize icon window horizontal distance */
+	wdecor_unmax_dw = 4,
+	/** Unmaximize icon window vertical distance */
+	wdecor_unmax_dh = 4
 };
 
@@ -98,16 +132,31 @@
 	}
 
-	rc = ui_pbutton_create(resource, "X", &wdecor->btn_close);
-	if (rc != EOK) {
-		free(wdecor->caption);
-		free(wdecor);
-		return rc;
-	}
-
-	ui_pbutton_set_cb(wdecor->btn_close, &ui_wdecor_btn_close_cb,
-	    (void *)wdecor);
-
-	ui_pbutton_set_decor_ops(wdecor->btn_close,
-	    &ui_wdecor_btn_close_decor_ops, (void *)wdecor);
+	if ((style & ui_wds_maximize_btn) != 0) {
+		rc = ui_pbutton_create(resource, "^", &wdecor->btn_max);
+		if (rc != EOK) {
+			ui_wdecor_destroy(wdecor);
+			return rc;
+		}
+
+		ui_pbutton_set_cb(wdecor->btn_max, &ui_wdecor_btn_max_cb,
+		    (void *)wdecor);
+
+		ui_pbutton_set_decor_ops(wdecor->btn_max,
+		    &ui_wdecor_btn_max_decor_ops, (void *)wdecor);
+	}
+
+	if ((style & ui_wds_close_btn) != 0) {
+		rc = ui_pbutton_create(resource, "X", &wdecor->btn_close);
+		if (rc != EOK) {
+			ui_wdecor_destroy(wdecor);
+			return rc;
+		}
+
+		ui_pbutton_set_cb(wdecor->btn_close, &ui_wdecor_btn_close_cb,
+		    (void *)wdecor);
+
+		ui_pbutton_set_decor_ops(wdecor->btn_close,
+		    &ui_wdecor_btn_close_decor_ops, (void *)wdecor);
+	}
 
 	wdecor->res = resource;
@@ -127,4 +176,5 @@
 		return;
 
+	ui_pbutton_destroy(wdecor->btn_max);
 	ui_pbutton_destroy(wdecor->btn_close);
 	free(wdecor->caption);
@@ -156,5 +206,9 @@
 
 	ui_wdecor_get_geom(wdecor, &geom);
-	ui_pbutton_set_rect(wdecor->btn_close, &geom.btn_close_rect);
+
+	if (wdecor->btn_max != NULL)
+		ui_pbutton_set_rect(wdecor->btn_max, &geom.btn_max_rect);
+	if (wdecor->btn_close != NULL)
+		ui_pbutton_set_rect(wdecor->btn_close, &geom.btn_close_rect);
 }
 
@@ -169,4 +223,16 @@
 {
 	wdecor->active = active;
+}
+
+/** Set maximized flag.
+ *
+ * Active window is the one receiving keyboard events.
+ *
+ * @param wdecor Window decoration
+ * @param maximized @c true iff window is maximized
+ */
+void ui_wdecor_set_maximized(ui_wdecor_t *wdecor, bool maximized)
+{
+	wdecor->maximized = maximized;
 }
 
@@ -289,5 +355,11 @@
 			return rc;
 
-		if ((wdecor->style & ui_wds_close_btn) != 0) {
+		if (wdecor->btn_max != NULL) {
+			rc = ui_pbutton_paint(wdecor->btn_max);
+			if (rc != EOK)
+				return rc;
+		}
+
+		if (wdecor->btn_close != NULL) {
 			rc = ui_pbutton_paint(wdecor->btn_close);
 			if (rc != EOK)
@@ -303,4 +375,24 @@
 }
 
+/** Send decoration maximize event.
+ *
+ * @param wdecor Window decoration
+ */
+void ui_wdecor_maximize(ui_wdecor_t *wdecor)
+{
+	if (wdecor->cb != NULL && wdecor->cb->maximize != NULL)
+		wdecor->cb->maximize(wdecor, wdecor->arg);
+}
+
+/** Send decoration unmaximize event.
+ *
+ * @param wdecor Window decoration
+ */
+void ui_wdecor_unmaximize(ui_wdecor_t *wdecor)
+{
+	if (wdecor->cb != NULL && wdecor->cb->unmaximize != NULL)
+		wdecor->cb->unmaximize(wdecor, wdecor->arg);
+}
+
 /** Send decoration close event.
  *
@@ -356,4 +448,6 @@
 {
 	gfx_coord_t frame_w;
+	gfx_coord_t btn_x;
+	gfx_coord_t btn_y;
 
 	/* Does window have a frame? */
@@ -376,4 +470,7 @@
 			geom->title_bar_rect.p1.x = wdecor->rect.p1.x;
 			geom->title_bar_rect.p1.y = wdecor->rect.p0.y + 1;
+
+			btn_x = geom->title_bar_rect.p1.x - 1;
+			btn_y = geom->title_bar_rect.p0.y;
 		} else {
 			geom->title_bar_rect.p0 = geom->interior_rect.p0;
@@ -381,4 +478,7 @@
 			geom->title_bar_rect.p1.y = geom->interior_rect.p0.y +
 			    wdecor_tbar_h;
+
+			btn_x = geom->title_bar_rect.p1.x - 1;
+			btn_y = geom->title_bar_rect.p0.y + 1;
 		}
 
@@ -386,4 +486,5 @@
 		geom->app_area_rect.p0.y = geom->title_bar_rect.p1.y;
 		geom->app_area_rect.p1 = geom->interior_rect.p1;
+
 	} else {
 		geom->title_bar_rect.p0.x = 0;
@@ -393,4 +494,6 @@
 
 		geom->app_area_rect = geom->interior_rect;
+		btn_x = 0;
+		btn_y = 0;
 	}
 
@@ -398,21 +501,17 @@
 	if ((wdecor->style & ui_wds_close_btn) != 0) {
 		if (wdecor->res->textmode == false) {
-			geom->btn_close_rect.p0.x =
-			    geom->title_bar_rect.p1.x - 1 - 20;
-			geom->btn_close_rect.p0.y =
-			    geom->title_bar_rect.p0.y + 1;
-			geom->btn_close_rect.p1.x =
-			    geom->title_bar_rect.p1.x - 1;
-			geom->btn_close_rect.p1.y =
-			    geom->title_bar_rect.p0.y + 1 + 20;
+			geom->btn_close_rect.p0.x = btn_x - 20;
+			geom->btn_close_rect.p0.y = btn_y;
+			geom->btn_close_rect.p1.x = btn_x;
+			geom->btn_close_rect.p1.y = btn_y + 20;
+
+			btn_x -= 20;
 		} else {
-			geom->btn_close_rect.p0.x =
-			    geom->title_bar_rect.p1.x - 1 - 3;
-			geom->btn_close_rect.p0.y =
-			    geom->title_bar_rect.p0.y;
-			geom->btn_close_rect.p1.x =
-			    geom->title_bar_rect.p1.x - 1;
-			geom->btn_close_rect.p1.y =
-			    geom->title_bar_rect.p0.y + 1;
+			geom->btn_close_rect.p0.x = btn_x - 3;
+			geom->btn_close_rect.p0.y = btn_y;
+			geom->btn_close_rect.p1.x = btn_x;
+			geom->btn_close_rect.p1.y = btn_y + 1;
+
+			btn_x -= 3;
 		}
 	} else {
@@ -422,4 +521,24 @@
 		geom->btn_close_rect.p1.y = 0;
 	}
+
+	/* Does window have a (un)maximize button? */
+	if ((wdecor->style & ui_wds_maximize_btn) != 0) {
+		if (wdecor->res->textmode == false) {
+			geom->btn_max_rect.p0.x = btn_x - 20;
+			geom->btn_max_rect.p0.y = btn_y;
+			geom->btn_max_rect.p1.x = btn_x;
+			geom->btn_max_rect.p1.y = btn_y + 20;
+		} else {
+			geom->btn_max_rect.p0.x = btn_x - 3;
+			geom->btn_max_rect.p0.y = btn_y;
+			geom->btn_max_rect.p1.x = btn_x;
+			geom->btn_max_rect.p1.y = btn_y + 1;
+		}
+	} else {
+		geom->btn_max_rect.p0.x = 0;
+		geom->btn_max_rect.p0.y = 0;
+		geom->btn_max_rect.p1.x = 0;
+		geom->btn_max_rect.p1.y = 0;
+	}
 }
 
@@ -495,4 +614,8 @@
 		return ui_wr_none;
 
+	/* Window is maximized? */
+	if (wdecor->maximized)
+		return ui_wr_none;
+
 	/* Position not inside window? */
 	if (!gfx_pix_inside_rect(pos, &wdecor->rect))
@@ -627,5 +750,11 @@
 	ui_wdecor_get_geom(wdecor, &geom);
 
-	if ((wdecor->style & ui_wds_close_btn) != 0) {
+	if (wdecor->btn_max != NULL) {
+		claim = ui_pbutton_pos_event(wdecor->btn_max, event);
+		if (claim == ui_claimed)
+			return ui_claimed;
+	}
+
+	if (wdecor->btn_close != NULL) {
 		claim = ui_pbutton_pos_event(wdecor->btn_close, event);
 		if (claim == ui_claimed)
@@ -635,5 +764,5 @@
 	ui_wdecor_frame_pos_event(wdecor, event);
 
-	if ((wdecor->style & ui_wds_titlebar) != 0) {
+	if ((wdecor->style & ui_wds_titlebar) != 0 && !wdecor->maximized) {
 		if (event->type == POS_PRESS &&
 		    gfx_pix_inside_rect(&pos, &geom.title_bar_rect)) {
@@ -646,10 +775,50 @@
 }
 
-/** Window decoration close button was clicked.
+/** Window decoration (un)maximize button was clicked.
  *
  * @param pbutton Close button
  * @param arg Argument (ui_wdecor_t)
  */
-static void ui_wdecor_btn_clicked(ui_pbutton_t *pbutton, void *arg)
+static void ui_wdecor_btn_max_clicked(ui_pbutton_t *pbutton, void *arg)
+{
+	ui_wdecor_t *wdecor = (ui_wdecor_t *) arg;
+
+	(void) pbutton;
+
+	if (wdecor->maximized)
+		ui_wdecor_unmaximize(wdecor);
+	else
+		ui_wdecor_maximize(wdecor);
+}
+
+/** Paint (un)maximize button decoration.
+ *
+ * @param pbutton Push button
+ * @param arg Argument (ui_wdecor_t *)
+ * @param pos Center position
+ */
+static errno_t ui_wdecor_btn_max_paint(ui_pbutton_t *pbutton,
+    void *arg, gfx_coord2_t *pos)
+{
+	ui_wdecor_t *wdecor = (ui_wdecor_t *)arg;
+	errno_t rc;
+
+	if (wdecor->maximized) {
+		rc = ui_paint_unmaxicon(wdecor->res, pos, wdecor_unmax_w,
+		    wdecor_unmax_h, wdecor_unmax_dw, wdecor_unmax_dh);
+	} else {
+		rc = ui_paint_maxicon(wdecor->res, pos, wdecor_max_w,
+		    wdecor_max_h);
+	}
+
+	return rc;
+}
+
+/** Window decoration close button was clicked.
+ *
+ * @param pbutton Close button
+ * @param arg Argument (ui_wdecor_t)
+ */
+static void ui_wdecor_btn_close_clicked(ui_pbutton_t *pbutton, void *arg)
 {
 	ui_wdecor_t *wdecor = (ui_wdecor_t *) arg;
Index: uspace/lib/ui/src/window.c
===================================================================
--- uspace/lib/ui/src/window.c	(revision 86fff9712bf6c2a6891033ebd6d851fba27dd6ca)
+++ uspace/lib/ui/src/window.c	(revision ad698f41375f8829d61f961fec3adf3cf7931200)
@@ -74,4 +74,6 @@
 };
 
+static void wd_maximize(ui_wdecor_t *, void *);
+static void wd_unmaximize(ui_wdecor_t *, void *);
 static void wd_close(ui_wdecor_t *, void *);
 static void wd_move(ui_wdecor_t *, void *, gfx_coord2_t *);
@@ -81,4 +83,6 @@
 
 static ui_wdecor_cb_t wdecor_cb = {
+	.maximize = wd_maximize,
+	.unmaximize = wd_unmaximize,
 	.close = wd_close,
 	.move = wd_move,
@@ -469,15 +473,14 @@
 }
 
-/** Resize/move window.
- *
- * Resize window to the dimensions of @a rect. If @a rect.p0 is not 0,0,
- * the top-left corner of the window will move on the screen accordingly.
+/** Resize or (un)maximize window.
  *
  * @param window Window
  * @param rect Rectangle
+ * @param scop Size change operation
  *
  * @return EOK on success or an error code
  */
-errno_t ui_window_resize(ui_window_t *window, gfx_rect_t *rect)
+errno_t ui_window_size_change(ui_window_t *window, gfx_rect_t *rect,
+    ui_wnd_sc_op_t scop)
 {
 	gfx_coord2_t offs;
@@ -545,9 +548,24 @@
 	}
 
-	/* dwindow can be NULL in case of unit tests */
+	/* dwindow can be NULL in case of unit tests or fullscreen mode */
 	if (window->dwindow != NULL) {
-		rc = display_window_resize(window->dwindow, &offs, &nrect);
-		if (rc != EOK)
-			goto error;
+		switch (scop) {
+		case ui_wsc_resize:
+			rc = display_window_resize(window->dwindow, &offs,
+			    &nrect);
+			if (rc != EOK)
+				goto error;
+			break;
+		case ui_wsc_maximize:
+			rc = display_window_maximize(window->dwindow);
+			if (rc != EOK)
+				goto error;
+			break;
+		case ui_wsc_unmaximize:
+			rc = display_window_unmaximize(window->dwindow);
+			if (rc != EOK)
+				goto error;
+			break;
+		}
 	}
 
@@ -597,4 +615,19 @@
 }
 
+/** Resize/move window.
+ *
+ * Resize window to the dimensions of @a rect. If @a rect.p0 is not 0,0,
+ * the top-left corner of the window will move on the screen accordingly.
+ *
+ * @param window Window
+ * @param rect Rectangle
+ *
+ * @return EOK on success or an error code
+ */
+errno_t ui_window_resize(ui_window_t *window, gfx_rect_t *rect)
+{
+	return ui_window_size_change(window, rect, ui_wsc_resize);
+}
+
 /** Set window callbacks.
  *
@@ -846,4 +879,28 @@
 	ui_window_send_unfocus(window);
 	ui_unlock(window->ui);
+}
+
+/** Window decoration requested window maximization.
+ *
+ * @param wdecor Window decoration
+ * @param arg Argument (window)
+ */
+static void wd_maximize(ui_wdecor_t *wdecor, void *arg)
+{
+	ui_window_t *window = (ui_window_t *) arg;
+
+	ui_window_send_maximize(window);
+}
+
+/** Window decoration requested window unmaximization.
+ *
+ * @param wdecor Window decoration
+ * @param arg Argument (window)
+ */
+static void wd_unmaximize(ui_wdecor_t *wdecor, void *arg)
+{
+	ui_window_t *window = (ui_window_t *) arg;
+
+	ui_window_send_unmaximize(window);
 }
 
@@ -948,4 +1005,28 @@
 }
 
+/** Send window maximize event.
+ *
+ * @param window Window
+ */
+void ui_window_send_maximize(ui_window_t *window)
+{
+	if (window->cb != NULL && window->cb->maximize != NULL)
+		window->cb->maximize(window, window->arg);
+	else
+		ui_window_def_maximize(window);
+}
+
+/** Send window unmaximize event.
+ *
+ * @param window Window
+ */
+void ui_window_send_unmaximize(ui_window_t *window)
+{
+	if (window->cb != NULL && window->cb->unmaximize != NULL)
+		window->cb->unmaximize(window, window->arg);
+	else
+		ui_window_def_unmaximize(window);
+}
+
 /** Send window close event.
  *
@@ -1014,4 +1095,61 @@
 	else
 		return ui_window_def_unfocus(window);
+}
+
+/** Default window maximize routine.
+ *
+ * @param window Window
+ * @return EOK on success or an error code
+ */
+errno_t ui_window_def_maximize(ui_window_t *window)
+{
+	errno_t rc;
+	gfx_rect_t old_rect;
+	gfx_rect_t rect;
+
+	old_rect = window->rect;
+
+	if (window->dwindow != NULL) {
+		rc = display_window_get_max_rect(window->dwindow, &rect);
+		if (rc != EOK)
+			return rc;
+	} else {
+		rect = window->ui->rect;
+	}
+
+	ui_wdecor_set_maximized(window->wdecor, true);
+
+	rc = ui_window_size_change(window, &rect, ui_wsc_maximize);
+	if (rc != EOK) {
+		ui_wdecor_set_maximized(window->wdecor, false);
+		return rc;
+	}
+
+	window->normal_rect = old_rect;
+	(void) ui_window_paint(window);
+	return EOK;
+}
+
+/** Default window unmaximize routine.
+ *
+ * @param window Window
+ * @return EOK on success or an error code
+ */
+errno_t ui_window_def_unmaximize(ui_window_t *window)
+{
+	errno_t rc;
+
+	ui_wdecor_set_maximized(window->wdecor, false);
+
+	rc = ui_window_size_change(window, &window->normal_rect,
+	    ui_wsc_unmaximize);
+	if (rc != EOK) {
+		ui_wdecor_set_maximized(window->wdecor, true);
+		printf("ui_window_size_change->error\n");
+		return rc;
+	}
+
+	(void) ui_window_paint(window);
+	return EOK;
 }