X11: Flush before returning from puglRealize()

This avoids bugs in plugins, because otherwise it's possible that size hints
are not available when the host embeds the UI.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/x11.c b/src/x11.c
index b9845fc..7800fed 100644
--- a/src/x11.c
+++ b/src/x11.c
@@ -470,6 +470,14 @@ puglRealize(PuglView* const view)
 
   puglDispatchSimpleEvent(view, PUGL_CREATE);
 
+  /* Flush before returning for two reasons: so that hints are available to the
+     view's parent via the X server during embedding, and so that the X server
+     has a chance to create the window (and make its actual position and size
+     known) before any children are created.  Potential bugs aside, this
+     increases the chances that an application will be cleanly configured once
+     on startup with the correct position and size. */
+  XFlush(display);
+
   return PUGL_SUCCESS;
 }