UWP : Share from a sharetarget

I've made a (kind of) image editor app that is a ShareTarget (obviously for images). This app can also share its content to other apps.

I've got two issues :

The first one appears when my app is called as a sharetarget by another app and then I want to share my app content.

On W10, it works just fine
On W10M (Creator Update & release2 insider builds) : the ShowShareUI() does nothing. In fact, the event "DataTransferManager_DataRequested" is not even raised...

I reproduced this behaviour on another image editor app on W10M (Phototastic) with success. So, it seems W10M can't manage two apps sharing content consecutively... Could you think of a workaround ?

The other issue is with the size of my app window on W10. As a sharetarget, the app has no minimize/maximize buttons. How to have my app window behave normally ?

Thank you very much.

Solution

I finished setting an info pop-up on W10M saying that sharing from a sharetarget is not possible on this platform. And as W10M is now dead, I Don't hope to see this behaviour modified.