EM_SETTABSTOPS top-level constant
The EM_SETTABSTOPS message sets the tab stops in a multiline edit control. When text is copied to the control, any tab character in the text causes space to be generated up to the next tab stop.
This message is processed only by multiline edit controls. You can send this message to either an edit control or a rich edit control.
const EM_SETTABSTOPS = 0x00CB;