win api.
i put text in combobox, then minimize window and maximize and combobox empty !
What is problem ?
https://www.youtube.com/watch?v=aDdFJdeiqrQ&ab_channel=Roman8139

invoke SendMessage,[combo10],wm_gettext,2,txt return always null in txt
Another combos work fine.

It would be better to send the code for creating your ComboBox instead of the stuff on the video. No one will guess where you made a mistake.

My mistake I create several combobox!
When I pressed button User Dll, I get several clicks.
And my Dll several times call Function createcombo.

First time I very weird this.
I not have problem with combobox, any time.
Until today.