fix(linux): apply the window title to frameless windows

setTitle skipped gtk_window_set_title whenever the window was created
with Frameless: true. newWindowImpl applies options.Title through that
same method, so a frameless window never received a title at all, and
every later SetTitle call was dropped too.

On Linux the title is not a titlebar: gtk_window_set_title writes the
WM_NAME/_NET_WM_NAME hints that taskbars, window switchers and pagers
label the window with. Decorations are governed separately, by
gtk_window_set_decorated in setFrameless/setBorderless, so titling an
undecorated window draws nothing.

The visible effect was that every window of a frameless application
carried the same label — the g_set_prgname fallback — leaving multiple
windows indistinguishable in the taskbar and in alt-tab.

Applies to both the GTK4 and GTK3 backends.

Author: julianstorer

v3/UNRELEASED_CHANGELOG.md

@@ -23,6 +23,7 @@ After processing, the content will be moved to the main changelog and this file
 
 ## Fixed
 <!-- Bug fixes -->
+- Apply the window title to frameless windows on Linux, so taskbars and window switchers can tell an application's windows apart in [PR](https://github.com/wailsapp/wails/pull/5960) by @julianstorer
 
 ## Deprecated
 <!-- Soon-to-be removed features -->

v3/pkg/application/linux_cgo.go

@@ -1306,11 +1306,13 @@ func (w *linuxWebviewWindow) present() {
 }
 
 func (w *linuxWebviewWindow) setTitle(title string) {
-	if !w.parent.options.Frameless {
-		cTitle := C.CString(title)
-		C.gtk_window_set_title(w.gtkWindow(), cTitle)
-		C.free(unsafe.Pointer(cTitle))
-	}
+	// Set unconditionally, frameless included: gtk_window_set_title writes the
+	// WM_NAME/_NET_WM_NAME hints that taskbars and window switchers label the
+	// window with, it does not draw a titlebar. Decorations are governed
+	// separately, by gtk_window_set_decorated.
+	cTitle := C.CString(title)
+	C.gtk_window_set_title(w.gtkWindow(), cTitle)
+	C.free(unsafe.Pointer(cTitle))
 }
 
 func (w *linuxWebviewWindow) setSize(width, height int) {

v3/pkg/application/linux_cgo_gtk3.go

@@ -1704,11 +1704,13 @@ func (w *linuxWebviewWindow) setOpacity(opacity float64) {
 }
 
 func (w *linuxWebviewWindow) setTitle(title string) {
-	if !w.parent.options.Frameless {
-		cTitle := C.CString(title)
-		C.gtk_window_set_title(w.gtkWindow(), cTitle)
-		C.free(unsafe.Pointer(cTitle))
-	}
+	// Set unconditionally, frameless included: gtk_window_set_title writes the
+	// WM_NAME/_NET_WM_NAME hints that taskbars and window switchers label the
+	// window with, it does not draw a titlebar. Decorations are governed
+	// separately, by gtk_window_set_decorated.
+	cTitle := C.CString(title)
+	C.gtk_window_set_title(w.gtkWindow(), cTitle)
+	C.free(unsafe.Pointer(cTitle))
 }
 
 func (w *linuxWebviewWindow) setIcon(icon pointer) {