Can you not assign devices to more than one dashboard? I'm trying to make a dashboard that can show all devices but i can't since most devices are already assigned to a dassboard.
In Apps under dashboards make sure you have the devices selected, sometimes it defaults to off on new dashboards.
It may be worth providing screenshots or at least a description of how you are trying to assign devices to your dashboards. There may be something you are either doing incorrectly or if there is some kind of bug then it will help to understand what you are trying to do.
To be clear - yes, you can assign any device to any dashboard.
Be aware that too many devices (ie hundreds) on a dashboard can slow down its loading time, which is why you need to select devices to add to them. The recommended approach is to have multiple dashboards with less devices on them. It is also possible to link one dashboard to another (I do that a lot).
to be simple, i want a device to be shown on two different dashboards.
It looks like you can only assign a device to one dashboard.
You’ll need to go to each child dashboard app to add it, but there is no limit to the number of dashboards that a device can be on. The same cannot be said for rooms.
I have every device assigned to a room.
Create dashboard(s) go to the child instance, click Choose devices, pick device. You can have 1 device in a 1000 dashboards if you like. As @Sebastien said though, don't add all your devices to one dashboard. It will slow loading to a crawl. Only add what you need to that dashboard.
Assigning devices to a Room (if you mean like below, on the Device page, using the Room option on the Device page) does not auto assign the device to a dashboard:
Rooms and Dashboards are two different things.
Yes, you can have one device in multiple dashboards.
As for Rooms, each device can only be in one room.