The following addons each add one or two simple features. Keeping track of one thread is simpler than creating a new thread for each addon, so they will all be collected here.
Making Less History: Download Version 1.0
One Window: Download Version 3.0
Science Relay: Download Version 5.1
Debug Input Stifle: Download Version 1.0
KerbNet Controller: Download Version 4.0
Flexible Docking: Download Version 7.0
EVA Struts: Download Version 5.0
@TK421 Are you sure the same thing doesn't happen without Portrait Stats? PS doesn't do anything with Kerbal levels, and if Strategia isn't being careful about capping Kerbal levels it could lead to problems when KSP tries to assign the correct star icon for the Kerbal portrait.