Quick and easy question - if you know the answer. I can't find it mentioned in the documentation. What do the icons circled in red mean?
Found in the built-in help (Workspace window):
The column that contains status information about option overrides can have one of three icons for each level in the project:
Blank There are no settings/overrides for this file/group.
Black check mark There are local settings/overrides for this file/group.
Red check mark There are local settings/overrides for this file/group, but they are either identical to the inherited settings or they are ignored because you use multi-file compilation, which means that the overrides are not needed.
Not sure about the icon itself, but the checkbox in that column indicates that a file (or folder) has an option override (source).