With the panel map client , you can choose your map client technology. Your choice has an affect on the tools and functions you can use. Functions that are unavailable will be grayed out. The Buttons appear when your map is published.
For example: the tool "TimeSliderTool.swf" will not work in the JS Map client. Therefore it is shown grayed out.

In Flex the tool is not shown grayed out. On the other side, some other tools don't work: