jump to end of sequence fails assertion

[westram]

Reproduce:

• run

  arb_edit4 $ARBHOME/UNIT_TESTER/run/TEST_prot.arb
  

• set cursor into BctFra12
• press HOME END END

⇒ fails ​assertion

Reason:

• target screen position is outside drawarea ⇒ cursor won't jump ⇒ position stays or gets wrong
  • either target position is too high
  • or drawarea is too small
    Note that the cursor shall be allowed to be placed behind the sequence, i.e. checked area might simply be wrong!

Notes:

• assertion introduced in [12129]
• see also #400