Scissors Appear On Plot On LT SPICE

I have seen this if I hit the F5 key when the plot has focus. It is just the delete mode for the cursor, and I think it will delete plots. Usually I use it in the schematic editor to delete components and wires, and I use the F6 key for copy. But usually I have been playing with the plot and then go to change the schematic without changing focus.

Usually when the analysis requires too much computing power it just slows to a crawl and sometimes pops up an error when it reaches some sort of singularity. Usually there is some component that has a problem or an unintentional LC network that goes into uncontrolled resonance.

Paul