If %TRUE, when the tab key is pressed and there is a selection, the selected text is indented of one level instead of being replaced with the \t characters. Shift+Tab unindents the selection.
whether to indent a block when tab is pressed.
1.8
See Implementation
If %TRUE, when the tab key is pressed and there is a selection, the selected text is indented of one level instead of being replaced with the \t characters. Shift+Tab unindents the selection.