Need help with interactive video please

Hi.

I have an interactive video on Storyline 2, operating on a slide layer.  At various specified points throughout the timeline (designated by cue points), the video pauses to display a message.  The idea is that the viewer must read each message (as the video is paused, he/she can take as long as necessary), and then click an OK button (which appears together with the message) to continue viewing the video thereafter.

These message pop-ups (caption boxes) and OK buttons (control buttons) are staggered over the length of the timeline, set for just 0.5 seconds in length (the video is paused at the time, so that's not an issue) and to only appear when the cue point is reached.  I then have a host of triggers set to pause the timeline and video when each cue point is reached, and then resume them both again once the OK button is clicked.

All good and well - everything works nicely in that respect.  However, I have now discovered an issue where clicking anywhere on the slide while the video is paused (not just on the OK button) will cause the video to resume playing while the timeline remains paused, throwing all subsequent cue point messages out of sync.  I have set the layer properties to pause the base layer's timeline, hide objects on the base layer and to prevent the user from clicking on the base layer, but nothing that I try can seemingly stop the video from playing if a click is made other than on the OK button.

Any ideas as to what I'm doing wrong?  Thanks