Slow disks cause issues in Installation Information panel when restoring

[Mgamerz]

When restoring individual files, or removing DLC mods in Installation Information, if the filesystem is taking a long time to return the file list (such as using a USB storage volume), this can cause race conditions where it duplicates the data shown in the panel. This needs to be handled to prevent issues.

[Mgamerz]

This issue was due to notifyDeleted() callback of DLC mod deletion method triggering an entire reload of modified data, rather than just the DLC mods list. On slow disks this could cause duplication as they'd both start and then later both finish, but the list of basegame files was only cleared at the start.