Use OnScreenNotification in kill window

Summary: Inform how to kill a window.

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D3724

killwindow.cpp

@@ -23,8 +23,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "abstract_client.h"
 #include "main.h"
 #include "platform.h"
+#include "osd.h"
 #include "unmanaged.h"
 
+#include <KLocalizedString>
+
 namespace KWin
 {
 
@@ -38,8 +41,11 @@ KillWindow::~KillWindow()
 
 void KillWindow::start()
 {
+    OSD::show(i18n("Select window to force close with left click or enter.\nEscape or right click to cancel."),
+              QStringLiteral("window-close"));
     kwinApp()->platform()->startInteractiveWindowSelection(
         [] (KWin::Toplevel *t) {
+            OSD::hide();
             if (!t) {
                 return;
             }