Fix size of ProjectDialog used by PLCOpenEditor

Disable scrolling for ProjectDialog, because otherwise very very small
windows is created.
This regression was introduced by 5701225 ("replaced normal panel with scrolled panel under project
properties").

#!/bin/sh

LC_ALL=ru_RU.utf-8

export DISPLAY=:42
Xvfb $DISPLAY -screen 0 1280x1024x24 &
sleep 1

ret=0
DELAY=400
KILL_DELAY=$(($DELAY + 30))
timeout -k $KILL_DELAY $DELAY pytest --timeout=10 ./tests/tools
ret=$?

pkill -9 Xvfb

exit $ret