This is the case, I use many iFrames in the same web Page, selection reflects on all iFrames , but Cancel Select doesn't reflect
and The Selection Bar doesn't show.
If you asked me why would I use many iFrames ?????
I will say for the sake of navigation since I tried to create a Navigation Widget and it worked inside the Qlik Sense Desktop only , but in the web Page it doesn't , that's why I split every Graph in a separate iFrame and I use my java script code for navigation.