Create an enumeration. Press the + button. Enter an item name, Foo. Tab out of that.
Expected: Value of Foo with (auto) assignment of value
Actual: Foo_ with (auto) assignment of value; an underscore is appended to what you typed as you leave the textbox.
Note: If you navigate away with the mouse rather than Tab, the underscore is not appended.
Note: If you save the finished enumeration it wants to add back an underscore to SOME of the item names. You can edit them out and re-save, switch away and back, and the underscores return.

The module is named Memory and contains various nested classes, e.g., MemoryTable.
If you look at the saved source, there's this oddly-indented version of the Enum:

... and then, the nested classes are all in their own source file without any reference to being nested in the containing module, just e.g. Public Class MemoryTable ... End Class.
It appears that only Studio knows that these are nested. And the declaration of the NativeType enum makes it look like it's the only thing within the Memory module.
The module and its contained members are all defined in the Shared section of the solution.
The only way to fix the underscores is to hand-edit the underlying file, then have Studio reload it.