Xcb: propagate stays-on-top or -below hints from window flags

Before, you had to first hide a window, then set the flags, then show
it again as the flags were only applied when showing the window. This
is unintuitive.

Task-number: QTBUG-49628
Change-Id: I240e633ac2581c0ff0e4f35dead1b79e15e15350
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index d76f1245e8..5d052a7ca1 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -1098,6 +1098,7 @@ void QXcbWindow::setWindowFlags(Qt::WindowFlags flags)
     }
 
     setWmWindowType(wmWindowTypes, flags);
+    setNetWmStateWindowFlags(flags);
     setMotifWindowFlags(flags);
 
     setTransparentForMouseEvents(flags & Qt::WindowTransparentForInput);
@@ -1333,6 +1334,15 @@ void QXcbWindow::updateNetWmStateBeforeMap()
     setNetWmStates(states);
 }
 
+void QXcbWindow::setNetWmStateWindowFlags(Qt::WindowFlags flags)
+{
+    changeNetWmState(flags & Qt::WindowStaysOnTopHint,
+                     atom(QXcbAtom::_NET_WM_STATE_ABOVE),
+                     atom(QXcbAtom::_NET_WM_STATE_STAYS_ON_TOP));
+    changeNetWmState(flags & Qt::WindowStaysOnBottomHint,
+                     atom(QXcbAtom::_NET_WM_STATE_BELOW));
+}
+
 void QXcbWindow::updateNetWmUserTime(xcb_timestamp_t timestamp)
 {
     xcb_window_t wid = m_window;
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index 41c4b4443d..1a8e031779 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -184,6 +184,7 @@ protected:
     void setNetWmStates(NetWmStates);
 
     void setMotifWindowFlags(Qt::WindowFlags flags);
+    void setNetWmStateWindowFlags(Qt::WindowFlags flags);
 
     void updateMotifWmHintsBeforeMap();
     void updateNetWmStateBeforeMap();