Your browser stores information that it downloads from your Synergist server to avoid having to download them every time - buttons, interface elements, graphics and the like, anything that is re-used over and over in the building of a web page is likely to be cached by your browser. Sometimes old versions of important elements are used from the cache instead of downloading the latest versions, which can lead to unpredictable behaviour.
In order to rectify this you must clear your browser cache, which will force a re-load of any items that need to be cached. The procedure is slightly different depending on your browser, but is generally very quick and easy. select your browser from the following page and follow the instructions: