Implement popup-style toplevels for menu editor on Wayland

The WPrefs menu editor creates standalone draggable windows for each
menu item via W_CreateTopView. On X11 these are override-redirect
windows. On Wayland they were becoming framed XDG toplevels with
taskbar entries, cluttering the desktop with phantom 'WINGs...' tabs.

Implementation:
1. New W_View flags.popup field, set by editmenu's standalone mode
2. wclient_wl: when realizing a popup view, set xdg_toplevel app_id
   to 'wings-popup' as a hint to the compositor
3. wmaker compositor: detect 'wings-popup' app_id in toplevel_map,
   set borderless + skip-taskbar + skip-switchpanel flags, then call
   wWindowConfigureBorders to rebuild the frame without decorations
4. New W_EventBackend->window_begin_move vtable method:
   - X11: returns False (caller runs manual drag loop)
   - Wayland: calls xdg_toplevel_move, returns True (compositor drives drag)
5. editmenu's dragMenu calls window_begin_move first; on Wayland the
   compositor handles the entire drag, so the manual loop is skipped

WINGs/WINGs/WINGsP.h.in

@@ -495,6 +495,10 @@ typedef struct W_EventBackend {
                                 int *x, int *y,
                                 unsigned int *width, unsigned int *height);
     void  (*move_window)(void *ectx, WNativeWindow window, int x, int y);
+    /* Begin interactive window move (Wayland: xdg_toplevel_move).
+     * Returns True if the backend will handle the move, False if the
+     * caller should run its own drag loop (X11). */
+    Bool  (*window_begin_move)(void *ectx, WNativeWindow window);
     WNativeWindow (*translate_coordinates)(void *ectx,
                                            WNativeWindow src, WNativeWindow dst,
                                            int src_x, int src_y,
@@ -1024,6 +1028,7 @@ struct W_View {
         unsigned int root:1;            /* is the root window */
         unsigned int mapWhenRealized:1; /* map the view when it's realized */
         unsigned int alreadyDead:1;     /* view was freed */
+        unsigned int popup:1;           /* popup-style toplevel (no frame, no taskbar) */
 
         unsigned int dontCompressMotion:1; /* motion notify event compress */
         unsigned int notifySizeChanged:1;

WINGs/wclient_wl.c

@@ -450,8 +450,13 @@ wl_client_toplevel_realize(struct W_View *view, int width, int height)
     /* Default app_id; the application can override via xdg_toplevel_set_app_id.
      * WPrefs and friends ought to call WMSetApplicationIconImage / set_title;
      * we'll plumb that next. */
-    xdg_toplevel_set_app_id(top->xdg_toplevel, "WINGs");
+    if (view->flags.popup) {
-    xdg_toplevel_set_title(top->xdg_toplevel, "WINGs Application");
+        xdg_toplevel_set_app_id(top->xdg_toplevel, "wings-popup");
+        xdg_toplevel_set_title(top->xdg_toplevel, "");
+    } else {
+        xdg_toplevel_set_app_id(top->xdg_toplevel, "WINGs");
+        xdg_toplevel_set_title(top->xdg_toplevel, "WINGs Application");
+    }
 
     /* Initial commit with no buffer so the compositor sends the first
      * configure.  We attach a real buffer in the configure handler. */
@@ -510,6 +515,25 @@ W_WLClientSetMinMaxSize(W_View *view)
     wl_surface_commit(top->surface);
 }
 
+Bool
+W_WLClientBeginMove(WNativeWindow window)
+{
+    extern uint32_t wlc_ptr_button_serial;
+    extern W_View *wlc_ptr_grab;
+    extern unsigned int wlc_ptr_button_state;
+    WLClientCtx *ctx = g_wlclient_ctx;
+    WLClientToplevel *top = wlc_top_find(window);
+    if (!ctx || !ctx->seat || !top || !top->xdg_toplevel) return False;
+    if (wlc_ptr_button_serial == 0) return False;
+    xdg_toplevel_move(top->xdg_toplevel, ctx->seat, wlc_ptr_button_serial);
+    /* Release implicit grab — the compositor now owns the input until
+     * the user releases the button. */
+    wlc_ptr_grab = NULL;
+    /* Clear pressed state so widgets don't think the button is still down */
+    wlc_ptr_button_state = 0;
+    return True;
+}
+
 /* ------------------------------------------------------------------ */
 /* Input: wl_pointer / wl_keyboard listeners                          */
 /* ------------------------------------------------------------------ */
@@ -540,11 +564,12 @@ wlc_xkb_mod_mask(struct xkb_state *state)
 /* Pointer state */
 static double  wlc_ptr_x, wlc_ptr_y;
 static uint32_t wlc_ptr_focus_serial;
+uint32_t wlc_ptr_button_serial;  /* serial of most recent button press */
 static WLClientToplevel *wlc_ptr_focused;
-static unsigned int wlc_ptr_button_state;
+unsigned int wlc_ptr_button_state;
 static unsigned int wlc_ptr_mods;
 static W_View *wlc_ptr_child_focus;
-static W_View *wlc_ptr_grab;  /* implicit grab: deliver events here while button held */
+W_View *wlc_ptr_grab;  /* implicit grab: deliver events here while button held */
 
 /*
  * Hit-test: find the deepest child view at (x,y) relative to the toplevel,
@@ -706,9 +731,11 @@ static void
 pointer_handle_button(void *data, struct wl_pointer *p, uint32_t serial,
                       uint32_t time, uint32_t button, uint32_t state)
 {
-    (void)p; (void)serial;
+    (void)p;
     WLClientCtx *ctx = data;
     if (!wlc_ptr_focused) return;
+    if (state == WL_POINTER_BUTTON_STATE_PRESSED)
+        wlc_ptr_button_serial = serial;
 
     /* Linux input event codes -> X-style button numbers. */
     unsigned int wmb;

WINGs/wevent_wl.c

@@ -219,6 +219,16 @@ static Bool wl_get_window_geometry(void *ectx, WNativeWindow w,
 static void wl_move_window(void *ectx, WNativeWindow w, int x, int y)
 { (void)ectx; (void)w; (void)x; (void)y; }
 
+/* Implemented in wclient_wl.c — calls xdg_toplevel_move on the client
+ * connection so the compositor handles the drag. */
+extern Bool W_WLClientBeginMove(WNativeWindow window);
+
+static Bool wl_window_begin_move(void *ectx, WNativeWindow window)
+{
+    (void)ectx;
+    return W_WLClientBeginMove(window);
+}
+
 static WNativeWindow wl_translate_coordinates(void *ectx,
     WNativeWindow src, WNativeWindow dst, int sx, int sy, int *dx, int *dy)
 { (void)ectx; (void)src; (void)dst; (void)sx; (void)sy;
@@ -317,6 +327,7 @@ const W_EventBackend W_EventBackendWL = {
     .query_pointer      = wl_query_pointer,
     .get_window_geometry = wl_get_window_geometry,
     .move_window        = wl_move_window,
+    .window_begin_move  = wl_window_begin_move,
     .translate_coordinates = wl_translate_coordinates,
     .get_root_window    = wl_get_root_window,
     .query_tree         = wl_query_tree,

WINGs/wevent_x11.c

@@ -435,6 +435,14 @@ x11_move_window(void *ectx, WNativeWindow window, int x, int y)
     XMoveWindow(ctx->dpy, (Window)window, x, y);
 }
 
+static Bool
+x11_window_begin_move(void *ectx, WNativeWindow window)
+{
+    (void)ectx; (void)window;
+    /* X11 uses manual drag loop with grab_pointer; no backend assist. */
+    return False;
+}
+
 static WNativeWindow
 x11_translate_coordinates(void *ectx, WNativeWindow src, WNativeWindow dst,
                           int src_x, int src_y, int *dst_x, int *dst_y)
@@ -759,6 +767,7 @@ const W_EventBackend W_EventBackendX11 = {
     .query_pointer       = x11_query_pointer,
     .get_window_geometry = x11_get_window_geometry,
     .move_window         = x11_move_window,
+    .window_begin_move   = x11_window_begin_move,
     .translate_coordinates = x11_translate_coordinates,
     .get_root_window     = x11_get_root_window,
     .query_tree          = x11_query_tree,

WPrefs.app/editmenu.c

@@ -383,6 +383,8 @@ static WEditMenu *makeEditMenu(WMScreen * scr, WMWidget * parent, const char *ti
 	} else {
 		mPtr->view = W_CreateTopView(scr);
 		mPtr->flags.standalone = 1;
+		if (mPtr->view)
+			mPtr->view->flags.popup = 1;
 	}
 	if (!mPtr->view) {
 		wfree(mPtr);
@@ -1050,6 +1052,17 @@ static void dragMenu(WEditMenu * menu)
 	unsigned blau;
 	WNativeWindow blaw;
 
+	if (menu->parent)
+		WTearOffEditMenu(menu->parent, menu);
+
+	/* Wayland: ask compositor to drive the move, then return.  X11:
+	 * fall through to manual drag loop. */
+	if (scr->eventBackend->window_begin_move
+	    && scr->eventBackend->window_begin_move(scr->eventBackendCtx,
+	                                            W_VIEW_DRAWABLE(menu->view))) {
+		return;
+	}
+
 	scr->eventBackend->get_window_geometry(scr->eventBackendCtx,
 		W_VIEW_DRAWABLE(menu->view), &dx, &dy, &blau, &blau);
 
@@ -1060,9 +1073,6 @@ static void dragMenu(WEditMenu * menu)
 
 	scr->eventBackend->grab_pointer(scr->eventBackendCtx, scr->rootWin, scr->defaultCursor);
 
-	if (menu->parent)
-		WTearOffEditMenu(menu->parent, menu);
-
 	while (!done) {
 		WMNextEvent(scr, &ev);
 

src/backend/wayland/wl_backend.c

@@ -1138,12 +1138,34 @@ handle_toplevel_map(struct wl_listener *listener, void *data)
              view->xdg_surface->toplevel->app_id  ? view->xdg_surface->toplevel->app_id  : "(none)",
              view->xdg_surface->toplevel->title   ? view->xdg_surface->toplevel->title   : "(none)");
 
+    /* Detect popup-style WINGs windows (menu editor items, etc.) — these
+     * need borderless presentation, no taskbar entry, and free positioning. */
+    const char *app_id_check = view->xdg_surface->toplevel->app_id;
+    int is_popup = (app_id_check && strcmp(app_id_check, "wings-popup") == 0);
+
     /* Phase 39/41: register the surface as a managed window. */
     {
         WScreen *scr = wScreenWithNumber(0);
         if (scr) {
             WWindow *wwin = wManageWindow(scr, view->id);
             if (wwin) {
+                if (is_popup) {
+                    /* Set borderless + skip-taskbar attributes */
+                    wwin->client_flags.no_border = 1;
+                    wwin->client_flags.no_titlebar = 1;
+                    wwin->client_flags.no_closable = 1;
+                    wwin->client_flags.no_miniaturizable = 1;
+                    wwin->client_flags.no_resizable = 1;
+                    wwin->client_flags.no_close_button = 1;
+                    wwin->client_flags.no_miniaturize_button = 1;
+                    wwin->client_flags.no_resizebar = 1;
+                    wwin->client_flags.skip_window_list = 1;
+                    wwin->client_flags.skip_switchpanel = 1;
+                    wwin->user_flags = wwin->client_flags;
+                    /* Rebuild frame without decorations */
+                    extern void wWindowConfigureBorders(WWindow *wwin);
+                    wWindowConfigureBorders(wwin);
+                }
                 int pid = wl_client_get_pid(view->id);
                 /* Phase 62: focus delivered by wManageWindow via wSetFocusTo
                  * (auto_focus=1 set in wl_screen_create_internals); the