fix: xwindow stack error

Author: zzxyb

examples/tinywl/helper.cpp

@@ -643,6 +643,10 @@ void Helper::setActivatedSurface(SurfaceWrapper *newActivateSurface)
 
     if (newActivateSurface) {
         newActivateSurface->stackToLast();
+        if (newActivateSurface->type() == SurfaceWrapper::Type::XWayland) {
+            auto xwaylandSurface = qobject_cast<WXWaylandSurface *>(newActivateSurface->shellSurface());
+            xwaylandSurface->restack(nullptr, WXWaylandSurface::XCB_STACK_MODE_ABOVE);
+        }
     }
 
     if (m_activatedSurface)

src/server/protocols/wxwaylandsurface.cpp

@@ -565,7 +565,12 @@ void WXWaylandSurface::close()
 
 void WXWaylandSurface::restack(WXWaylandSurface *sibling, StackMode mode)
 {
-    handle()->restack(*sibling->handle(), static_cast<xcb_stack_mode_t>(mode));
+    if (sibling) {
+        handle()->restack(*sibling->handle(), static_cast<xcb_stack_mode_t>(mode));
+        return;
+    }
+
+    handle()->restack(nullptr, static_cast<xcb_stack_mode_t>(mode));
 }
 
 WAYLIB_SERVER_END_NAMESPACE