The top panel and Unity Dash dont apear.
Aslo Window Decoration donw apear (neither on top nor on left/right or bot) some windows are full screen all the time due to this, others in normal size (cant full screen)
Try resetting Compiz, as there may be some problem with it. Many time while trying diffrent desktop environment it also occurs.
To reset all the Compiz settings (this includes all the plugins settings, etc.) to the default values, open a terminal (don't run it with ALT + F2! Generally while everything is fine the top panel and launcher gets disappear after running the first command but will show up after the second one so use a terminal) and type:
gconftool-2 --recursive-unset /apps/compiz-1
gconftool-2 --recursive-unset /apps/compizconfig-1
unity --reset
You can also try:
rm -rf ~/.config/compiz-1/compizconfig
