Control Addin - refresh issue on Tablet

Wildcard

Hello,
I've been adding the signature control addin from this link :
https://blogs.msdn.microsoft.com/nav/2014/10/09/extensibility-for-the-microsoft-dynamics-nav-tablet-client/

It is working perfectly on the windows client after 2-3 modifications but on the tablet I have an issue with the refresh.
If I open the page, I need to click on refresh to load the image.
The same after adding the signature and clicking on accept. If I don't click on refresh nothing is shown, anyway the signature is still saved in the table.

I've been playing around with currpage.Update / refresh ...
Also trying with timer functionality ... sendkeys ...

As I'm not very confortable with the C# part, I don't know if there is something to do there ...

Do you have an idea or did you manage something like this successfully ?

Thanks for your help.

Wildcard