#73 Extended Goto dialog is too small

[Thomas Mueller]

The extended Goto dialog is not high enough to display all lines in the list. This only happens with some high DPI monitors.

This could be fixed by either calculating the required height or simply making the dialog sizeable and storing its size so the user can fix it himself.

(Reported by Peter Aschbacher)

[Thomas Mueller]

The required height of the list box is now dynamically calculated and the dialog height adjusted accordingly.

(This works for me, but I never actually experienced that problem, so I don't know whether it works for Peter too.)