gtk3: New Folder dialog from Templates dialog doesn't get keyboard focus

ctrl+shift+N, and click new folder, no keyboard input is accepted.

The dialogs don't get keyboard events, because the keyboard events
go to the top level window because of...

commit 011ce226e8
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Tue Jan 19 13:22:10 2016 +0000

    Resolves: tdf#99604 ungrab modal dialogs

(should be tdf#96604) which stripped away the grab from the sub dialog

but I did that because menu dropdowns from comboboxes inside modal
dialogs didn't receive mouse focus otherwise.

I had set our "modal" dialogs to be truly modal and triggering that
problem with

commit 8d5822983e
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Mon Dec 14 11:36:50 2015 +0000

    Related: rhbz#1290014 gtk3: use gtk_window_set_modal on modal dialogs

    which makes modal dialogs (which are most of them) place correctly
    under wayland. Modeless ones are still uselessly shoved far to the
    left, but this makes things near usable and gives the same "graying
    into the bg" effect for the main window as other gtk apps

which I still contend is "a good thing"

if we stop removing the grab from the modal dialog, then we still have
the problem that the menu dropdowns from comboboxes inside modal dialogs
don't receive mouse focus otherwise.

After trying to add/remove grabs around showing/hiding menus we run
into another pit of trouble

(commit 72e6a1365c
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Wed May 4 16:29:35 2016 +0100)

so, lets save the widget that has the grab before showing our first
menu, clear the grab, and restore it on hiding the first menu again.

and still ditch that metacity hack around thing at this point too

I truly hate this crap

Change-Id: If10e758585f156b33680b8d40355302cc1ae72f3

vcl/inc/unx/gtk/gtkframe.hxx

@@ -303,6 +303,7 @@ class GtkSalFrame : public SalFrame
     static GdkNativeWindow findTopLevelSystemWindow( GdkNativeWindow aWindow );
 
     static int m_nFloats;
+    static GtkWidget* m_pGrabWidgetBeforeShowFloats;
 
     bool isFloatGrabWindow() const
     {

vcl/unx/gtk3/gtk3gtkframe.cxx

@@ -104,6 +104,7 @@
 using namespace com::sun::star;
 
 int GtkSalFrame::m_nFloats = 0;
+GtkWidget* GtkSalFrame::m_pGrabWidgetBeforeShowFloats = nullptr;
 
 #if defined ENABLE_GMENU_INTEGRATION
 static GDBusConnection* pSessionBus = nullptr;
@@ -1424,21 +1425,6 @@ void GtkSalFrame::Show( bool bVisible, bool bNoActivate )
                 SetDefaultSize();
             setMinMaxSize();
 
-            if( isFloatGrabWindow() &&
-                m_pParent &&
-                m_nFloats == 0 &&
-                ! getDisplay()->GetCaptureFrame() )
-            {
-                /* #i63086#
-                 * outsmart Metacity's "focus:mouse" mode
-                 * which insists on taking the focus from the document
-                 * to the new float. Grab focus to parent frame BEFORE
-                 * showing the float (cannot grab it to the float
-                 * before show).
-                 */
-                 m_pParent->grabPointer( true, true );
-            }
-
             if( ! bNoActivate && (m_nStyle & SalFrameStyleFlags::TOOLWINDOW) )
                 m_bSetFocusOnMap = true;
 
@@ -1449,6 +1435,9 @@ void GtkSalFrame::Show( bool bVisible, bool bNoActivate )
                 m_nFloats++;
                 if( ! getDisplay()->GetCaptureFrame() && m_nFloats == 1 )
                 {
+                    m_pGrabWidgetBeforeShowFloats = gtk_grab_get_current();
+                    if (m_pGrabWidgetBeforeShowFloats)
+                        gtk_grab_remove(m_pGrabWidgetBeforeShowFloats);
                     grabPointer(true, true);
                     GtkSalFrame *pKeyboardFrame = m_pParent ? m_pParent : this;
                     pKeyboardFrame->grabKeyboard(true);
@@ -1470,6 +1459,11 @@ void GtkSalFrame::Show( bool bVisible, bool bNoActivate )
                     GtkSalFrame *pKeyboardFrame = m_pParent ? m_pParent : this;
                     pKeyboardFrame->grabKeyboard(false);
                     grabPointer(false);
+                    if (m_pGrabWidgetBeforeShowFloats)
+                    {
+                        gtk_grab_add(m_pGrabWidgetBeforeShowFloats);
+                        m_pGrabWidgetBeforeShowFloats = nullptr;
+                    }
                 }
             }
             gtk_widget_hide( m_pWindow );
@@ -2414,13 +2408,6 @@ void GtkSalFrame::SetModal(bool bModal)
     if (!m_pWindow)
         return;
     gtk_window_set_modal(GTK_WINDOW(m_pWindow), bModal);
-    if (bModal)
-    {
-        //gtk_window_set_modal bTrue adds a grab, so ungrab here. Quite
-        //possibly we should alternatively call grab_add grab_ungrab on
-        //show/hide of menus ?
-        gtk_grab_remove(m_pWindow);
-    }
 }
 
 gboolean GtkSalFrame::signalTooltipQuery(GtkWidget*, gint /*x*/, gint /*y*/,