Meshes disappear after a proofreading event, forcing users to wait to do anything

[ceesem]

After merging or splitting neurons, the meshes will go away for a couple of seconds. This can be frustrating if you're actively proofreading, because there's no other way to navigate around the neuron than waiting for the meshes to reload, even though in both split and merge cases the best guess is that most mesh fragments are exactly the same.

Instead of immediately removing the mesh from the viewer, I wonder if there is a better way to convey data to the user about the split. For example, change the appearance (color or opacity or saturation — wireframe mode maybe?) of a mesh after the proofreading operation was reported as successful, but still let users interact with it until the new meshes are more completely ready to show.