Author: Tomas Rutkauskas

I have some forms with the property WindowState set to wsMaximized. The problem is 
that some forms are hiding the taskbar. I can't find the problem since some others 
forms are working fine.

Answer:

Solve 1:

If I'm right, the only way to get correctly maximized windows (regarding the 
taskbar and other "taskbar like" windows) is using API functions:


1   var
2     x: pointer;
3     r: TRect;
4   begin
5     x := Addr(r);
6     SystemParametersInfo(SPI_GETWORKAREA, 0, x, 0);
7     Left := 0;
8     Width := r.Right;
9     Top := 0;
10    Height := r.Bottom;
11    { ... }



Solve 2:

This seems to be a particular problem when you do it in the forms OnCreate event. 
To fix it add a handler for the WM_GETMINMAXINFO message:


private
12  { Private declarations }
13  
14  procedure wmGetMinMaxInfo(var msg: TWMGetMinMaxInfo); message WM_GETMINMAXINFO;
15  
16    procedure TForm1.wmGetMinMaxInfo(var msg: TWMGetMinMaxInfo);
17    var
18      r: TRect;
19    begin
20      SystemParametersInfo(SPI_GETWORKAREA, 0, @r, 0);
21      with msg.MinMaxInfo^ do
22      begin
23        ptMaxSize := r.BottomRight;
24        ptMaxPosition := r.TopLeft;
25      end;
26    end;



If your form is set to Position := poDesigned and WindowState := wsMaximized, then don't set any value for Constraints. Otherwise the form won't maximize correctly at runtime, if the Windows taskbar is resized.