This works normally as expected:

iw = fpl.ImageWidget([np.random.rand(100, 512, 512)] * 6)
iw.show()

Initial black subplots because scaling is off:

iw = fpl.ImageWidget([np.random.rand(100, 512, 512)] * 5)
iw.show()

Another example:

iw = fpl.ImageWidget([np.random.rand(100, 512, 512)] * 8)
iw.show()

with 9 works as expected:

iw = fpl.ImageWidget([np.random.rand(100, 512, 512)] * 9)
iw.show()

I think this has to do with auto_scale() being called somewhere on the last subplot. If you first click the auto-scale button in the 5 subplots/images situation to make the images visible, and then call iw.gridplot[-1, -1].auto_scale() it reproduces the wrong auto-scaling.

@clewis7 is this what you were getting? It might be from the toolbar refactor. We need more tests 🥲