When you select single space on code pane all spaces in code become selected. To me it is look very weird. If I'm not alone on this feeling we can integrate issue 16962 <https://pharo.fogbugz.com/f/cases/16962/Code-pane-should-not-show-all-spaces...> For more details current behavior is: If you select "self", all "self"s in the code pane are selected with "secondary selection color" If you select "." all dots are selected. If you select a space-char all spacess are selected If you select a tab-char all tabs are selected ... With my fix you will not see secondary selection on any separators (space ,tab). It was my first impression when I start to navigate/select text by command left/right. And spaces selection during this process looks to me very bad.