Thank you for the solution.
It was great.
If so, a few questions:.
1. How to change the location because it is inside the image and does not cause the full picture to be seen.
2. Why is UserData used? While it could do without UserData, as an example…
I built a page with a guibuilder that has a few widgets.
And I created a picture with GUI_DrawBitmap on WM_PAINT.
I just want this scroll bar, but I do not know what to do.
If it is possible to help me.