I work with OxygenOO latest Version on Win Vista 32bit Home Premium.
Since updating to the latest Version there is a strange effect when marking text and opening de context menu - it's very slow.
That's not in Calc….
That's a known in OOO, nothing to do with OOOP.
Just use the workaround mentioned in the bug report (extension menu). OOO 3.1 is dead slow in filtering (calc) too.