https://www.ut99.org/viewtopic.php?f=5&t=5695&p=98694#
Explanations:
- brackets are announcing a new group
- NumButtons - defines number of buttons which are about to be used - my case 18 pieces from 0 to 17;
- Button definition - sample taken "Button1"
Parameter 1 - "Align Camera on Selected Actor" - means tool-tip - name of button;
Parameter 2 - "UDAlignCam" - means the name of BMP file - ICON used by this button;
Parameter 3 - "CAMERA ALIGN" - means the internal command which Editor executes for selected actor.
ALL new Buttons must have a BMP ICON file for clicking on them (as BrushBuilders). All Buttons must be announced by using "NumButtons" value.