Here comes he RunT!

Kinc/Backends/System/Linux/Sources/kinc/backend/funcs.h

@@ -29,6 +29,7 @@ struct linux_procs {
 	int (*window_display)(int window_index);
 	void (*window_show)(int window_index);
 	void (*window_hide)(int window_index);
+	void (*window_set_foreground)(int window_index);
 	void (*window_set_title)(int window_index, const char *title);
 	void (*window_change_mode)(int window_index, kinc_window_mode_t mode);
 	kinc_window_mode_t (*window_get_mode)(int window_index);

Kinc/Backends/System/Linux/Sources/kinc/backend/linuxunit.c

@@ -59,6 +59,7 @@ void kinc_linux_init_procs() {
 		procs.window_resize = kinc_wayland_window_resize;
 		procs.window_show = kinc_wayland_window_show;
 		procs.window_hide = kinc_wayland_window_hide;
+		procs.window_set_foreground = kinc_wayland_window_set_foreground;
 		procs.count_windows = kinc_wayland_count_windows;
 
 		procs.mouse_can_lock = kinc_wl_mouse_can_lock;
@@ -111,6 +112,8 @@ void kinc_linux_init_procs() {
 		procs.window_resize = kinc_x11_window_resize;
 		procs.window_show = kinc_x11_window_show;
 		procs.window_hide = kinc_x11_window_hide;
+		procs.window_set_foreground = kinc_x11_window_set_foreground;
+
 		procs.count_windows = kinc_x11_count_windows;
 
 		procs.display_init = kinc_x11_display_init;

Kinc/Backends/System/Linux/Sources/kinc/backend/window.c.h

@@ -80,6 +80,10 @@ void kinc_window_hide(int window_index) {
 	procs.window_hide(window_index);
 }
 
+void kinc_window_set_foreground(int window_index) {
+	procs.window_set_foreground(window_index);
+}
+
 void kinc_window_set_title(int window_index, const char *title) {
 	procs.window_set_title(window_index, title);
 }

Kinc/Backends/System/Linux/Sources/kinc/backend/x11/window.c.h

@@ -145,6 +145,16 @@ void kinc_x11_window_hide(int window_index) {
 	xlib.XUnmapWindow(x11_ctx.display, window->window);
 }
 
+void kinc_x11_window_set_foreground(int window_index) {
+	struct kinc_x11_window *window = &x11_ctx.windows[window_index];
+	if (window->window == None) {
+		return;
+	}
+	xlib.XRaiseWindow(x11_ctx.display, window->window);
+	xlib.XSetInputFocus(x11_ctx.display, window->window, RevertToParent, CurrentTime);
+	xlib.XFlush(x11_ctx.display);
+}
+
 kinc_window_mode_t kinc_x11_window_get_mode(int window_index) {
 	return x11_ctx.windows[window_index].mode;
 }

Kinc/Backends/System/Windows/Sources/kinc/backend/window.c.h

@@ -392,6 +392,11 @@ void kinc_window_hide(int window_index) {
 	UpdateWindow(windows[window_index].handle);
 }
 
+void kinc_window_set_foreground(int window_index) {
+	SetForegroundWindow(windows[window_index].handle);
+	SetFocus(windows[window_index].handle);
+}
+
 void kinc_window_set_title(int window_index, const char *title) {
 	wchar_t buffer[1024];
 	MultiByteToWideChar(CP_UTF8, 0, title, -1, buffer, 1024);

Kinc/Sources/kinc/window.h

@@ -139,6 +139,11 @@ KINC_FUNC void kinc_window_show(int window);
 /// </summary>
 KINC_FUNC void kinc_window_hide(int window);
 
+/// <summary>
+/// Set a window to the foreground.
+/// </summary>
+KINC_FUNC void kinc_window_set_foreground(int window);
+
 /// <summary>
 /// Sets the title of a window.
 /// </summary>