Kerbal Space Program

Symptoms: This cause constant re-instantiation of the PAW by UIPartActionController .Update(), generating huge lag that result in PAWs becoming very unresponsive.

To reproduce :

In the editor, add a crewable and crewed root part (only one)
Open the PAW

Compile and add the following code is compiled against KSP 1.11.2:

// ************************************************
using KSP.UI;

public class TestCrewModule : PartModule {
bool called = false;
void Update() {
if (HighLogic.LoadedSceneIsEditor) {
if (!called) {
VesselCrewManifest originalVesselManifest = CrewAssignmentDialog.Instance.GetManifest();
CrewAssignmentDialog.Instance.RefreshCrewLists(originalVesselManifest, true, true);
called = true;
}
var manifest = KSP.UI.CrewAssignmentDialog.Instance.GetManifest();
}
}
}
// ************************************************

Add the following to parts with crew capacity:

MODULE
    {
        name = TestCrewModule
    }

You can use the following patch with ModuleManager to make it easier:
@PART[*]:HAS[#CrewCapacity[>0]]:FINAL {
MODULE {
name = TestCrewModule
}
}

Workarounds:

I did notice that removing/restoring crew also "cleared" the condition in the editor, so I'm assuming that my adding/removing parts was particular to command pods (since that was the first panel open in the part tray) as they would trigger crew info refreshing.

Add a second crewed part, then remove it