Multimonitor-Problem with TBXMDI when MainForm on secondary monitor

[plashenkov]

Issue imported from Google Code:
https://code.google.com/p/tbxlib/issues/detail?id=3

Reported by bernd.ott [at] quantendrehung.de, Jan 30, 2013

You need at least two monitors.
put the primary monitor on left side.
the secondary monitor hast to be on right side and in a higher position in windows.

see screenshot

use an mdi application.
put tbxmdi on form.
put mainform on secondary monitor in maximized mode.
put mdichild in max. mode.
click mdi close button.

you get an exception:
Exception class: ERangeError
Exception address: 0064F929

Stack list, generated 30.01.2013 15:38:01
[0064F924] TBXMDI.TTBXMDIButtonsItem.ItemClick + $4C
[004033BE] System.ErrorAt + $16
[0064F924] TBXMDI.TTBXMDIButtonsItem.ItemClick + $4C
[005B1CC8] TB2Item.TTBCustomItem.Click + $A8
[005B1BA7] TB2Item.TTBCustomItem.ClickWndProc + $BB
[004303AC] Classes.StdWndProc + $14
[0049093C] Forms.TApplication.ProcessMessage + $FC
[00490976] Forms.TApplication.HandleMessage + $A
[00490C6B] Forms.TApplication.Run + $B3

---

sorry, component is ttbxmdihandler

---

file tbxmdi fails at:
SendMessage(ChildForm.Handle, WM_SYSCOMMAND, Cmd, GetMessagePos);

GetMessagePos delivers a negative position.

http://msdn.microsoft.com/en-us/library/windows/desktop/ms646360(v=vs.85).aspx

maybe that parameter can be 0 or -1. but that has to be testet

---

My suggest patch:

Index: TBXMDI.pas
===================================================================
--- TBXMDI.pas  (revision 19)
+++ TBXMDI.pas  (working copy)
@@ -286,7 +286,7 @@
   begin
     Form := Application.MainForm.ActiveMDIChild;
     if Assigned(Form) then
-      SendMessage(Form.Handle, WM_SYSCOMMAND, TTBXCustomItem(Sender).Tag, GetMessagePos);
+      SendMessage(Form.Handle, WM_SYSCOMMAND, TTBXCustomItem(Sender).Tag, -1);
   end;
 end;

@@ -606,7 +606,7 @@
         Cmd := SC_CLOSE
       else
         Cmd := SC_MINIMIZE;
-      SendMessage(ChildForm.Handle, WM_SYSCOMMAND, Cmd, GetMessagePos);
+      SendMessage(ChildForm.Handle, WM_SYSCOMMAND, Cmd, -1);
     end;
   end;
 end;