When a value is modified or a specific symbol is focused, the text is colored red, and the background grey, which provides bad contrast. This is changed in updated versions of winIDEA, but the older default color stays in saved options values.
Delete the *.XTRF file to see the change.
1. Click Start or Cortana search icon in Windows 10.
2. In the search box type in %appdata% and select the folder.
3. You should be located in AppData/Roaming file. Delete [USER]\AppData\Roaming\ASYST\winIDEA\winIDEA.xtrf.