Did you ever start to do something in CATIA V5 then suddenly find out that you can't see a certain icon? No need to worry. it's there, you're not blind. Here are some suggestions for how to hunt for it.
In the View menu>Toolbars, you can enable any of the listed ones. Always keep it to a minimum so that you don't clutter your user interface.
Make sure that you don't see any double arrows (or Chevrons) in the bottom-right corner of your CATIA screen. If so, then you need to pull out all these toolbars out until you find it.
If all fails, go to Tools>Customize, Toolbars Tab. then click Restore Position button. This will bring CATIA back to the original factory UI settings.
For those who would like a reference page of most icons in their respective workbenches, I've uploaded a copy of icon screen shots. Click here to download.