#1375 operations guis are incorrectly set as you switch focus

[Jeremy Faden]

I found that suddenly the filters would get reset as you switch focus:

1. plot vap+inline:outerProduct(ones(200),findgen(20))+randn(200,20)/10
2. plot below vap+inline:outerProduct(ones(200),findgen(20))+randn(200,20)/10
3. focus on top plot, set filters to "|slice0(54)"
4. focus on bottom plot, set filter to |slice1(0)"
5. focus on top plot. filter is cleared.

Also changes from the GUI don't go into the history, so this can be very annoying...