The font used in the IDL editor can be changed using the "Preferences" dialog box. By default, the font that is set for workbench is used.
Changing the font setting
Select "Window" > "Preferences" from the menu bar. The "Preferences" dialog box is displayed.
Select "IDL" > "Editor" in the left pane. The "Editor" page is displayed.
Click the "General" tab.
Click "Change". The "Font" dialog box is displayed.
Change "Font", "Font style", and "Size" as necessary.