[Bug 50193] New: Minimizing a window of a Delphi app leads to a window completely disappearing without any ability to restore it

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=50193

Bug ID: 50193
           Summary: Minimizing a window of a Delphi app leads to a window
                    completely disappearing without any ability to restore
                    it
           Product: Wine
           Version: 1.2-rc2
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Keywords: download, regression, source, testcase
          Severity: normal
          Priority: P2
         Component: winex11.drv
          Assignee: [e-mail]
          Reporter: [e-mail]
   Regression SHA1: 61e50e15ba45ad54655f98619f5ef33917033165
      Distribution: ---

Created attachment 68708
  --> https://bugs.winehq.org/attachment.cgi?id=68708
test app (source + binary)

Applications created with Delphi create secondary top level windows without
WS_EX_APPWINDOW style set, and minimizing such a window leads to a window
completely disappearing without any ability to restore it.

This is a regression caused by

commit 61e50e15ba45ad54655f98619f5ef33917033165
Author: Alexandre Julliard 
Date:   Fri May 28 12:14:43 2010 +0200

winex11: Map zero-size windows and set an empty window region for them.

Admittedly Windows behaviour is weird: it minimizes such windows in an MDI
style with desktop as an MDI client and Delphi window as an MDI child.

https://source.winehq.org/patches/data/196455 is an attempt to fix this
regression.

Before this patch: no taskbar window for a normal or minimized owned window.
After this patch: no taskbar window for normal owned window, after a window
being minimized a taskbar button appears, after a window being restored a
taskbar button gets removed.

Attachment contains a simple test app (source + binary) that reproduces this
problem.