How to add a new module to a plugin?

[mjrmls]

Adding a Module to Plugin crashes Unreal Engine: "Assertion failed: IsValid() UE_4.26\...\Templates/SharedPointer.h [Line: 890]"

Update : In the code generated for the “Editor Standalone Window” preset, in MyPluginEditorStyle.cpp, there is this function: TSharedRef< FSlateStyleSet > FMyPluginEditorStyle::Create() { TSharedRef< FSlateStyleSet > Style = MakeShareable(new FSlateStyleSet("MyPluginEditorStyle")); Style->SetContentRoot(IPluginManager::Get().FindPlugin("MyPluginEditor")->GetBaseDir() / TEXT("Resources")); Style->Set("MyPluginEditor.OpenPluginWindow", new IMAGE_BRUSH(TEXT("ButtonIcon_40x"), Icon40x40)); r…