When one of our pen-grip mice connects to a supported app like Jump Desktop, or Microsoft RD Client it technically stops functioning as a regular mouse and instead uses our own systems to communicate directly with the app. This is how we were able to add support for our mice before iOS itself had any mouse support of its own.

Now that iOS does have partial mouse support via AssistiveTouch using a supported remote desktop app will temporarily prevent iOS from recognizing your mouse. To get it working in iOS again after using one of these apps your mouse will just need to be switched off and on again. We are looking into ways to prevent this from happening, but for now this is the best solution.

The alternative solution would be to disable the bespoke mouse support in your remote desktop app. This would allow you to seamlessly use the AssistiveTouch across all apps, however you would lose access to some basic mouse functions such as middle click and the scroll wheel, also right click would require a long press.