[PATCH] user32: Update exstyle when setting style in SetWindowLong.

[Piotr Caban]

Hi Alexandre,

On 10/4/21 8:06 PM, Alexandre Julliard wrote:
> Piotr Caban <piotr at codeweavers.com> writes:
> 
>> Rockstar Games Launcher checks extended window style and exits if it
>> is incorrect.
>>
>> Signed-off-by: Piotr Caban <piotr at codeweavers.com>
>> ---
>>   dlls/user32/tests/win.c | 18 +++++++++++++++++-
>>   dlls/user32/win.c       | 15 ++++++++++++---
>>   2 files changed, 29 insertions(+), 4 deletions(-)
> 
> Do we need to store that flag at all? Could it be synthesized from the
> other ones instead?
> 
No, it can't be synthesized while preserving (what I believe is) a bug 
in native. The same pair of style/exstyle produces different 
WS_EX_WINDOWEDGE depending on the context.

We currently have different conditions for setting WS_EX_WINDOWEDGE in 
SetWindowLong and in CreateWindow. We also have tests covering the 
difference. I've played a little more with this tests and current code 
is not fully correct (e.g. styles passed to CBT_CREATEWND are different 
than on Windows 10, changing style in hook also sometimes produces 
different results).

I think the code may be more readable if we introduce a helper for 
setting exstyle. I will prepare a patch that does it. Hopefully it will 
also make the CreateWindow special case more visible.

Thanks,
Piotr