Fix a bug when switching fullscreen mode

The code assumed that a window gets resized when it enters/leaves the fullscreen
mode. This was needed because the code for resizing a window hides and shows the
titlebars.

However, it is possible for a window to enter/leave fullscreen mode without
getting resized, because it already has the correct geometry. In this case,
titlebars were not handled correctly.

This commit fixes that by forcing a resize to the current geometry when the
fullscreen flag is toggled.

Signed-off-by: Uli Schlachter <psychon@znc.in>

objects/client.c

@@ -836,6 +836,8 @@ client_set_fullscreen(lua_State *L, int cidx, bool s)
         c->fullscreen = s;
         luaA_object_emit_signal(L, abs_cidx, "request::fullscreen", 1);
         luaA_object_emit_signal(L, abs_cidx, "property::fullscreen", 0);
+        /* Force a client resize, so that titlebars get shown/hidden */
+        client_resize_do(c, c->geometry, true);
         stack_windows();
     }
 }