Out of ALL the dynamic blocks I've made, and all the different properties I've used, by far the most complicated ones deal with Chaining. I really hope sometime here soon we'll get some good examples on how to use the Chaining feature. Because I for one struggle each and every time I need to use it. I pretty much just try to stay away. The most complicated part I find is trying to decipher which parameters should be set to allow chaining "YES" and which ones should remain set to "NO".
When the Chain actions property of a parameter is set to Yes, the actions associated with that parameter are activated when that parameter is changed by another action.
Make sure to be careful not to inadvertently select the geometry which the chained parameter affects when adding a chained parameter to the selection set of an action. Otherwise some actions may be performed twice on the same geometry. This will cause geometry to move really quickly and mess with your block.
Attached is 2 examples I have using the Chaining option. I've made a good of blocks and these are the only 2 blocks I have that use this option. So, if your blocks don't have any chaining options don't worry about it. If they need them good luck!! Feel free to e-mail your block when working with Chaining and I'll attempt to help. Download chaining_example_1.dwg