ac4ce26d_1_0_Help____Editor__Appearance__Item
[Description] Select this check box to have IntelliJ IDEA display white spaces or tabs (depending on the Code Style settings made in the Tabs and Indents pane of the General page. You can select the following options: Leader - select this check box to add white spaces before your code line. Inner - select this check box to display white spaces inside the line of your code. Trailing - select this check box to display white spaces after the code line. [Item] 
Show whitespaces
IntelliJ IDEA 14.1.0 Help :: Editor. Appearance