Zitat:
WS_TABSTOP
Specifies a control that can receive the keyboard focus when the user presses the TAB key. Pressing the TAB key changes the keyboard focus to the next control with the WS_TABSTOP style.
You can turn this style on and off to change dialog box navigation. To change this style after a window has been created, use SetWindowLong.
Zitat:
The WM_NEXTDLGCTL message is sent to a dialog box procedure to set the keyboard focus to a different control in the dialog box.
Syntax
WM_NEXTDLGCTL
WPARAM wParam
LPARAM lParam;
Parameters
wParam
If lParam is TRUE, this parameter identifies the control that receives the focus. If lParam is FALSE, this parameter indicates whether the next or previous control with the WS_TABSTOP style receives the focus. If wParam is zero, the next control receives the focus; otherwise, the previous control with the WS_TABSTOP style receives the focus.
lParam
The low-order word indicates how the system uses wParam. If the low-order word is TRUE, wParam is a
handle associated with the control that receives the focus; otherwise, wParam is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus.
Entsprechend dürfte der Stil nicht korrekt gesetzt sein, da die
Win32-
API das korrekt handelt. Ich weiß nicht inwieweit die Eigenschaft von Delphi und
API zusammenhängen (ein Zusammenhang ist zu vermuten) aber bei meinen Tests funktioniert es. Versuch mal explizites Setzen des obigen Stils.