Tool Settings Window

Hi there.
I have just recently upgraded to Connect Edition Update 10 - version 10.10.00.23. I'm not sure how I did it, but yesterday I did something that made the tool settings window disappear. The Tool Settings Window does not appear on the screen for any tool I select. For example, if I click the "Place Arc" tool, it allows me to create an arc but I am unable to choose how I create the arc. I'm sure it a is a simple setting to fix but I can't for the life of me find it.
Thanks in advance, Gordon