The DER_DBG_TAB environment variable affects how the debugger expands tab characters in a source or mixed view within a Source pane. The value for this variable is an integer, indicating the number of spaces to convert a tab character into. Unlike DER_DBG_TABGRID, DER_DBG_TAB does not cause the debugger to place tabbed information in specific columns; it simply results in each tab in the displayed files being converted to the indicated number of spaces.
Note: If DER_DBG_TABGRID has been set to a nonzero value, the setting of DER_DBG_TAB has no effect.