I have smartshapes defined as buttons to emulate stylized check boxes. The smartshapes have normal and visited states only, with the visited state displaying a check mark. Each button calls the same shared action to toggle the display and set a variable. All show up as interactive controls in the tab order, yet the spacebar does nothing when I tab and attempt to activate the control. I ended up having to create unique shortcuts for each control and override the auto-accessibility to explicitly describe the shortcut, which is something I did not want to do. I also tried adding hover and down states to the buttons but that had no effect.

This issue reported for CP7, so I am creating a new thread as it is happening in CP17 as well. The CP7 issue was described here: https://forums.adobe.com/thread/1637398.  In that case, the issue related to using transparent buttons.  In my case, I am using smartshapes as buttons.