Event selection window is not scrollable

[pglvdm]

When one is debugging and have a large list of possible events to choose from it would be handly if it would be possible to scroll in the window.

[joey-coleman]

Example:

channels
  a:nat
process Test = begin 
@ ||| i in set {1,...,50} @ [{}] a.i-> Skip
end

Note the CML Event Options window has no visible scrollbar, and we cannot scroll by other means.

[joey-coleman]

Fixed in 773b2e