In the left frame, there is the "opponents" section where the name of the opponent to be fought crops up. The problem with the current design is that often, esp when speed clicking, the mouse hovers above the "fight" link and at times strays onto the "delete" link which is directly above it. Then, if you've realised what you've done, you need to check the battle log to find out whom you've deleted.
An ergonomically efficient design would be to place the "edit" or "specify" link directly above the "fight" link, so that even if the stray click ends up there, you perform a more forgiving action rather than the delete.
This should involve nothing more than a simple juxtaposition of the links, so its simple to modify. Please :)