is it me or is it Gimp?

[Ofnuts]

In the attached XCF (small!: 5x5pixels), there are 4 layers: 1, 2, 3 and the problem layer, "Numpy Ops" (which is identical to "1", with one red and one blue square). For me, this layer:

• Shows in the Layers list, but behave as a transparent layer in the Image window.
  
• Remains invisible if I copy/paste it over itself (Ctrl-C,Ctrl-V,Ctrl-H)
  
• Produces a visible copy if I copy it as a new layer (Ctrl-C,Ctrl-V,Ctrl-Shift-N)
  
• Can be painted over, but the painting only shows in the Layers list
  

Is it the same for you?

The layer is produced using the "pixel region" API for Python...