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Proposed icons attached.
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Then next instruction should look more like the next line icon.
Also, what about a little rearranging:
At the moment we have: Debug, RunToCursor, Next line, Next instruction, Step Into, Step Out, Pause, Stop.
I think the following order is better: Debug, RunToCursor, Next line, Step Into, Step Out, Next instruction, Step into instruction, Pause, Stop.