Hello,
first of all thank you for the help and tips.
I have found a solution to my problem.
I have attached my solution here and in the first post:
https://fileforums.com/showpost.php?...&postcount=116
Maybe it's just a simple workaround, but it's ok for me...

( >>
Procedure to hide + show WizardForm )
Now all
buttons + text are shown correctly too.
Best regards
Nordi
UPDATE : Solution found and attached !!!
Solution 1 = managed with WinAPI function > SendWindowsText
Solution 2 = managed with WizardForm.Caption
>> works without the styles too
SOLUTION3 => no flickering Wizard :
https://fileforums.com/showpost.php?...&postcount=121