Add note about use of Fl_Window::decorated_h() under the X11 platform.

1 files changed, 3 insertions, 0 deletions

diff --git a/FL/Fl_Window.H b/FL/Fl_Window.H
index 4ce65f3bc..ddcea3fbe 100644
--- a/FL/Fl_Window.H
+++ b/FL/Fl_Window.H
@@ -519,6 +519,9 @@ public:
    added by the window manager.
 
    Same as h() if applied to a subwindow, or if window is not yet mapped.
+   \note Under X11, it's not possible to compute decorated_h() - h()
+   to obtain the height of the titlebar <b> during a resize operation</b>.
+   That computation is to best done when the window is first mapped.
    */
   int decorated_h() const;