I can't try to reproduce it, because you are using custom color scheme and .
Anyway, it looks the [..] item is FOCUSED, dwg file is selected - mouse cursor is over the dwg file, so this is "hot track".
Try it with default settings, command line parameters, or portable version - your current installation will be preserved.
FAQ – FreeCommander
Try to provide exact steps to reproduce, how you clicked the dwg file - left clicked it once?
Are you using one of the options "By click on ..."? If so, file is just selected if you click the extension, NOT FOCUSED, it's a feature, not bug.
More info:
https://freecommander.com/fchelpxe/en/General4.html
https://freecommander.com/fchelpxe/en/S ... CMode.html
EDIT: BTW try default white or default dark color scheme, here you can find which item is selected/focused/hot item:
Color Schemes - Files - FreeCommander Forum
With NC-Mode different colors are used in Dark grey flat default scheme, for selection it's red text and no background.