After checking "Completed", setting a seed triggers a new cleaving task

[hubbardp]

Say you have a cleaving task for body 1, and you check "Completed" to cleave off supervoxels making bodies 2 and 3. If you stay on body 1 (i.e., don't press "Next" or "Prev") and then press the spacebar to set a new seed on body 1, the tool can infer that you want to do further cleaving of what is left in body 1 after cleaving off 2 and 3.

So the tool should raise a dialog (concisely) explaining this situation and asking you to confirm. Then the tool would uncheck "Completed", really delete the meshes for 2 and 3, and otherwise reinitialize for a new cleaving task, with all the seed colors (other than body 1's color) being reusable for new bodies to be cleaved off.

Shin-ya confirmed that this behavior makes sense to him.