Do you mean the bookmarks sidebar or do you want to change the way a menu drop down list opens?

The latter is determined automatically by Firefox and you can't change that.

If you mean something then can you attach a screenshot to sow what you mean?

• http://en.wikipedia.org/wiki/Screenshot

Use a compressed image type like PNG or JPG to save the screenshot and make sure that you do not exceed the maximum file size (1 MB).

Hi Cor-el I mean bookmarks side bar. Can we move to right side?

You can look at:

• RightBar: https://addons.mozilla.org/firefox/addon/rightbar/