Toggle for "Active Layer Not Visible" warning
Option to disable "The Active Layer Is Not Visible" warning
A toggle, either in the eraser tool's options, or in global options to suppress the "Active Layer Is Not Visible" warning
Use cases
When using the layer below the current layer as a guide for what to erase, it would be much more efficient to be able to toggle the visibility of the layer, rather than messing with the opacity, which is the only current method of doing this. This was possible in older versions of GIMP, however, it has since been changed to throw a warning message, and it no longer supports this behavior, with no option to re enable it.
Edit: I'm not sure how to mark this issue as feature, sorry about that.
Edited by Michael Natterer