From c6cc416977228b35d161cbc3a506e993922e7573 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 21 Oct 2018 16:45:24 +0200
Subject: [PATCH] Propagate InformFirstDirection() to wxCollapsiblePane pane

As wxCollapsiblePane doesn't use sizers for layout (and while this could
be changed for the generic version, it still wouldn't fix the problem
for the native one), default InformFirstDirection() implementation
forwarding it to the window sizer doesn't work for it and we need to
explicitly let the contents of wxCollapsiblePane know about the
available size.
---
 include/wx/collpane.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/include/wx/collpane.h b/include/wx/collpane.h
index 54ccd73650..168dc7c06e 100644
--- a/include/wx/collpane.h
+++ b/include/wx/collpane.h
@@ -43,6 +43,23 @@ public:
 
     virtual wxString GetLabel() const wxOVERRIDE = 0;
     virtual void SetLabel(const wxString& label) wxOVERRIDE = 0;
+
+    virtual bool
+    InformFirstDirection(int direction,
+                         int size,
+                         int availableOtherDir) wxOVERRIDE
+    {
+        wxWindow* const p = GetPane();
+        if ( !p )
+            return false;
+
+        if ( !p->InformFirstDirection(direction, size, availableOtherDir) )
+            return false;
+
+        InvalidateBestSize();
+
+        return true;
+    }
 };