Ok what I would do is make each topic or whatever a seperate sprite. With this having been done, create a textbox along side your chart. This will hold the paragraph about whatever topic you click on. Name this text member something like topicParagraph Then, make all you text members (just keep them in the cast). Name them someting like topic1, topic2, etc. Next make a behavior script like this:
on mouseenter me
case me.spritenum of
1:member("topicParagraph"

.text = member("topic1"

.text
2:member("topicParagraph"

.text = member("topic2"

.text
3:member("topicParagraph"

.text = member("topic3"

.text
end case
end
Next apply this (drag it from the cast to the sprites) script to all the seperate parts of your diagram. The way this scirpt works is simple. Based on what the sprite number is of the part of the chart you click on is, it puts into the paragraph textbox the contents of a specified text member. What's nice about a script like this is that you only need 1 script for all your sprites. If this doesn't work right or you need some help, just ask.