In fullscreen mode, the window property of cocoaView may not be the key
window, and the current implementation would not re-grab cursor by left click
in fullscreen mode after ungrabbed in fullscreen mode with hot-key ctrl-opt-g.

This patch used value of isFullscreen as a short-cirtuit condition for
relative input device grabbing.

Signed-off-by: Chen Zhang <tgfbeta@me.com>
---
 ui/cocoa.m | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/ui/cocoa.m b/ui/cocoa.m
index 474d44cb9f..aa7cf07368 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -901,7 +901,12 @@ QemuCocoaView *cocoaView;
         case NSEventTypeLeftMouseUp:
             mouse_event = true;
             if (!isMouseGrabbed && [self screenContainsPoint:p]) {
-                if([[self window] isKeyWindow]) {
+                /*
+                 * In fullscreen mode, the window of cocoaView may not be the
+                 * key window, therefore the position relative to the virtual
+                 * screen alone will be sufficient.
+                 */
+                if(isFullscreen || [[self window] isKeyWindow]) {
                     [self grabMouse];
                 }
             }
-- 
2.21.0