Prevent toolbox getting lost when minimising windows

On X, window managers don't like WM_TRANSIENT_FOR being altered while a
window is visible; this meant that if you opened TikZiT and opened a
second main window and minimised the main window that had focus, the
toolbox and properties window would both disappear, with no way to get
them back (well, almost - the properties window could be retreived with
the menu item that shows/hides it).

Tested with KWin, Metacity (Gnome 2's WM), Mutter (Gnome 3) and xfwm4
(XFCE 4).  Metacity and Mutter still behave a little oddly - you have to
click one of the main windows *twice* to get it to focus.  KWin and
xfwm4 work fine.

7 files changed, 31 insertions, 8 deletions

diff --git a/tikzit/src/gtk/Application.m b/tikzit/src/gtk/Application.m
index 89fb7fd..99ad24d 100644
--- a/tikzit/src/gtk/Application.m
+++ b/tikzit/src/gtk/Application.m
@@ -387,8 +387,8 @@ Application* app = nil;
 
     [contextWindow setDocument:[window document]];
 
-    [contextWindow setTransientFor:window];
-    [toolBox setTransientFor:window];
+    [contextWindow attachToWindow:window];
+    [toolBox attachToWindow:window];
 
     [[NSNotificationCenter defaultCenter]
         addObserver:self
diff --git a/tikzit/src/gtk/ContextWindow.h b/tikzit/src/gtk/ContextWindow.h
index 64ecd19..fcad9df 100644
--- a/tikzit/src/gtk/ContextWindow.h
+++ b/tikzit/src/gtk/ContextWindow.h
@@ -43,7 +43,7 @@
             andEdgeStylesModel:(EdgeStylesModel*)esm;
 
 - (void) present;
-- (void) setTransientFor:(Window*)parent;
+- (void) attachToWindow:(Window*)parent;
 
 - (void) loadConfiguration:(Configuration*)config;
 - (void) saveConfiguration:(Configuration*)config;
diff --git a/tikzit/src/gtk/ContextWindow.m b/tikzit/src/gtk/ContextWindow.m
index 9f376a0..d8e9d20 100644
--- a/tikzit/src/gtk/ContextWindow.m
+++ b/tikzit/src/gtk/ContextWindow.m
@@ -119,8 +119,8 @@ static gboolean props_window_delete_event_cb (GtkWidget *widget, GdkEvent *event
     gtk_window_present (GTK_WINDOW (window));
 }
 
-- (void) setTransientFor:(Window*)parent {
-    gtk_window_set_transient_for (GTK_WINDOW (window), [parent gtkWindow]);
+- (void) attachToWindow:(Window*)parent {
+    utility_window_attach (GTK_WINDOW (window), [parent gtkWindow]);
 }
 
 - (void) loadConfiguration:(Configuration*)config {
diff --git a/tikzit/src/gtk/ToolBox.h b/tikzit/src/gtk/ToolBox.h
index 7076417..60074c1 100644
--- a/tikzit/src/gtk/ToolBox.h
+++ b/tikzit/src/gtk/ToolBox.h
@@ -36,7 +36,7 @@
 
 - (void) show;
 - (void) present;
-- (void) setTransientFor:(Window*)w;
+- (void) attachToWindow:(Window*)parent;
 
 - (void) loadConfiguration:(Configuration*)config;
 - (void) saveConfiguration:(Configuration*)config;
diff --git a/tikzit/src/gtk/ToolBox.m b/tikzit/src/gtk/ToolBox.m
index 4b6aa0a..c6d2ccf 100644
--- a/tikzit/src/gtk/ToolBox.m
+++ b/tikzit/src/gtk/ToolBox.m
@@ -231,8 +231,8 @@ static void tool_button_toggled_cb (GtkWidget *widget, ToolBox *toolBox);
     gtk_window_present (GTK_WINDOW (window));
 }
 
-- (void) setTransientFor:(Window*)parent {
-    gtk_window_set_transient_for (GTK_WINDOW (window), [parent gtkWindow]);
+- (void) attachToWindow:(Window*)parent {
+    utility_window_attach (GTK_WINDOW (window), [parent gtkWindow]);
 }
 
 - (void) loadConfiguration:(Configuration*)config {
diff --git a/tikzit/src/gtk/gtkhelpers.h b/tikzit/src/gtk/gtkhelpers.h
index 4da949b..e4b79b8 100644
--- a/tikzit/src/gtk/gtkhelpers.h
+++ b/tikzit/src/gtk/gtkhelpers.h
@@ -55,4 +55,6 @@ void widget_clear_error (GtkWidget *widget);
 
 void text_buffer_clear_tag (GtkTextBuffer *buffer, GtkTextTag *tag);
 
+void utility_window_attach (GtkWindow *util_win, GtkWindow *parent_win);
+
 // vim:ft=objc:sts=2:sw=2:et
diff --git a/tikzit/src/gtk/gtkhelpers.m b/tikzit/src/gtk/gtkhelpers.m
index e6b1aef..9d26af5 100644
--- a/tikzit/src/gtk/gtkhelpers.m
+++ b/tikzit/src/gtk/gtkhelpers.m
@@ -251,4 +251,25 @@ void text_buffer_clear_tag (GtkTextBuffer *buffer, GtkTextTag *tag) {
     gtk_text_buffer_remove_tag (buffer, tag, &start, &end);
 }
 
+void utility_window_attach (GtkWindow *util_win, GtkWindow *parent_win) {
+    if (parent_win == gtk_window_get_transient_for (util_win))
+        return;
+
+    // HACK: X window managers tend to move windows around when they are
+    //       unmapped and mapped again, so we save the position
+    gint x, y;
+    gtk_window_get_position (util_win, &x, &y);
+
+    // HACK: Altering WM_TRANSIENT_FOR on a non-hidden but unmapped window
+    //       (eg: when you have minimised the original parent window) can
+    //       cause the window to be lost forever, so we hide it first
+    gtk_widget_hide (GTK_WIDGET (util_win));
+    gtk_window_set_focus_on_map (util_win, FALSE);
+    gtk_window_set_transient_for (util_win, parent_win);
+    gtk_widget_show (GTK_WIDGET (util_win));
+
+    // HACK: see above
+    gtk_window_move (util_win, x, y);
+}
+
 // vim:ft=objc:ts=8:et:sts=4:sw=4