Build Mode Glitch/Panel disappears

i hate when that one happens when it has happened to me i try  one of a couple of  things before ( if it totally freezes on me i may have to ctrl+alt+del to taskmanger out of it  ) hit F1 to go back to live mode then back to build/buy  hit F5 to bring up the options menu go to edit town try save a copy of the lot to the libiary to try not to loose the work i have done then back edit town click on the lot in edit town and back to build/buy

the reason if possiable  for saving a copy of the lot to the libiary is if you get a fair bit of work done on the lot and something happens you just need to place your latest save of the lot back ingame and can carry on without having to redo  a lot of work

my newest build i'm building i have at the least 10 copies of my lot in the libiary which reminds me i need to delete the older ones i build get so far save it to the libary etc etc  

IF you have to taskmanger our and end task once the game closes down then go to the electronicsarts/thesims3/CurrentGame.sims open that folder if files are in there delete them they will be no good it is normal for files to build up in there while playing/building when we save and quit the folder empties out BUT if we get a crash or have to taskmanger out the files remain behind