I don’t know if anyone else gets this… but after working with Blender on a long session it really starts to become sluggish and slow when moving around in the 3D window. I don’t know what’s causing this (not clearing memory??) but I’ve accidently found a ‘fix’ that seems to work, I’m posting it here in case it’s of use to other BlenderHeads experiencing the same/similar problem.
the fix temp solution
In the 3D window (leave mouse over tha viewport) just hit the ‘P’ key to start the game engine, let it kick in (you might get the old ‘no camera’ warning depending on what you’re doing) and then hit ‘Esc’ to come out of game mode. You should then find that Blender is back to it’s usual self. Rinse and repeat everytime Blender starts to become sluggish (you usually have to quit and restart to get Blender back up to speed).
Obviously this only works with Blender version that can run the game engine (with the ‘P’ key). I’m currently using 2.26.