As I've previously said I'm running on old hardware with a P4. My machine can become cpu bound - plenty of memory available.
AlienBob's version of 126.96.36.199 has problems with dialogs in that they seem to get stuck, especially the format cells dialog in calc which just appeared empty. To resolve I s had to give it a nudge by clicking inside the dialog at an appropriate place! Also forms, in base, were a real problem I'd open a form an two versions of the same form would appear, hang there for about 5 seconds then one would disappear.
The RPM version from Libreoffice build from slackbuild.org was better, the dialogs didn't require nudging.The forms, in base, still had the same problems.
My present hypothesis is that the form gets built in a arbitrary position and size at the same time as building the same form according to the attributes contained in a config file held somewhere in ~/.config/libreoffice/4/user. When both forms are built it throws away the arbitrarily built one.
I've tested it on windows XP and it behaves in the same way as the RPM version above though appreciably faster.
I'm sure the above explanation helps no one but at least it is recorded for all to see!
If this doesn't resolve itself in the next version of Libreoffice I will raise a bug report. Though I suspect if I run it on more modern hardware I might not see an issue.