BeginPopupModal() cannot receive null as its second parameter

[MarcosCobena]

Steps to reproduce

1. Create/open an Evergine project with support to ImGui
2. In its source code, type: ImGui.BeginPopupModal("foo", null) (actually, any method receiving ref bool)

What I expect

To allow passing a null reference to indicate I am not insterested in preserving state in any variable/field.

What I get

The compiler does not allow, given the method signature, to pass null in any form. I have tried as well to declare a bool? field but the compiler stops as well, nor I have found any casting or similar.

Versions

ImGui.Net: 1.78.0.0