jump to species broken in IRS tree (again)

[westram]

Pressing the JUMP button does not work correctly in IRS (=folded dendrogram view).

• first fix was done by #111
• current problems were not introduced by [15665]

Details:

• behavior in IRS view:
  • near the top of the → positions species/group near center of viewport.
  • near the bottom of the → positions species/group (for) above the folding line
  • the bigger the (display size), the worse the problem.
    Unfold whole groups → gets really bad
• ???

(Un-)related(?) JUMP problem:

• when a group (which is vertically bigger than size of viewport) gets unfolded
  ⇒ group completely jumps out of view (in IRS view AND normal dendrogram view)

[westram]

To work-around the problem until it's fixed, set
Properties/Tree options/[auto-focus]/On species change
to do nothing and scroll manually or use the JUMP button.