From b6dd78878f86ca83fa8cf803f290c5a275afaaaf Mon Sep 17 00:00:00 2001
From: dmitry <dmitry@lazarus-ide.org>
Date: Thu, 13 Sep 2018 20:33:47 +0000
Subject: [PATCH] cocoa: update tab page view resizing for negative sizes

git-svn-id: trunk@58974 -
---
 lcl/interfaces/cocoa/cocoatabcontrols.pas | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lcl/interfaces/cocoa/cocoatabcontrols.pas b/lcl/interfaces/cocoa/cocoatabcontrols.pas
index d831257eee..2f2ff637c4 100644
--- a/lcl/interfaces/cocoa/cocoatabcontrols.pas
+++ b/lcl/interfaces/cocoa/cocoatabcontrols.pas
@@ -108,6 +108,7 @@ type
   public
     tabView: TCocoaTabControl;
     tabPage: TCocoaTabPage;
+    procedure setFrame(arect: NSRect); override;
   end;
 
 function IndexOfTab(ahost: TCocoaTabControl; atab: NSTabViewItem): Integer;
@@ -303,6 +304,20 @@ begin
   end;
 end;
 
+{ TCocoaTabPageView }
+
+procedure TCocoaTabPageView.setFrame(arect: NSRect);
+begin
+  // It's possible for a tab page view to go in negative height.
+  // However, automatic resizing flags (for whatever reason) prevent
+  // TCocoaTabPageView to go into negative height (remaining at 0 pixels)
+  // The code below makes sure that resizing is actually happening
+  if Assigned(superView) and (superView.frame.size.height < arect.size.height) then
+    arect.size.height := superView.frame.size.height;
+
+  inherited setFrame(arect);
+end;
+
 { TCocoaTabPage }
 
 function TCocoaTabPage.lclGetCallback: ICommonCallback;