Most of the times, you'd want to configure 'Click' event and give common functionality to the contents of a dynamic layout. If more than one controls in your layout do the same function, consider giving them a common purpose by configuring action on DL rather than on individual control. I can give you 2 examples where I found this technique very useful -
In a shopping cart application, on top right corner you typically have a cart icon (first control) and a number that reflects you cart quantity (second control). Clicking on any of these opens up an overlay that shows you cart items. you may club the action together by configuring action on dynamic layout.
If you have ever tried to build an Amazon like app with Pega (the UI is possible and I have built it), you'd find building buttons that occupy 100% width difficult. But, with actions on dynamic layout, you no longer need a button. you can just use a layout as your 'tap' target.
A lot of thought has gone into building a good UX with Pega 7 and this is a very good example of that. You nail a very important concept of a good UX with this configuration - understanding intent of the user. On devices with smaller real estate like mobile phones, setting a common context further helps you 'declutter' the UI.
I'm looking at your screenshot and it looks like you want to execute an Action when someone clicks on a tab. Tab is not part of a dynamic layout and that is why action may not be working. Can you try clicking on something inside a dynamic layout and outside grid, because grid again has it's own event mechanism. Is the issue seen foe a stand-alone dynamic layout with few controls?