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This is still an issue in the latest version.
I keep having to manually change the code every time I updated.

OH, my bad. It didn't say "Update" on Unity Asset Store so I assumed incorrectly that I had the latest version.

I forgot I had updated it already for a different project...

You can mark this as resolve or delete if you want.

LudiqGUIUtility.cs

EditorWindow_ShowModal = typeof(EditorWindow).GetMethod("ShowModal", BindingFlags.Instance | BindingFlags.NonPublic);

2019.4+? (TODO: Determine which version of Unity changed this)

EditorWindow_ShowModal = typeof(EditorWindow).GetMethod("ShowModal", BindingFlags.Instance | BindingFlags.Public);

shift + C didn't seem to work but shift + alt seems fine

I'll try changing the code later today.

Maybe it could be shift + C?

This Unity Project was started in 2018.3