If the device can be controlled by one device only, the second device was either not mapped properly, or the issue is related to the number of TCP connections the third-party device can accept.
If your third-party device is a single TCP, it can be controlled by one source only.
So it all depends on how many controlling devices (such as XTouch Control, Solaro FR1 controller, Xilica Designer) are running at the same time. Each one counts as 1 TCP connection to the third-party device.
For example, let's use a PJLink projector.
If in the controller design, the user places a PJLink power button in the controller design schematic, the controller will automatically setup a TCP when project is loaded.
If in the XTouch Control design, the user drags in any control items from the PJLink projector to the XTouch control page, then when project design is loaded to the XTouch, XTouch will automatically setup a TCP connection to the PJLInk projector.
If Xilica Designer has a PJLink projector in the project, when putting the project ONLINE, Xilica Designer will try to setup a TCP to PJLink projector.
If your third-party device is a single TCP and you'd like to control it using an XTouch Control device, go online with the project and then exit the Xilica Designer desktop app. The XTouch Control device should be able to control the third-party device.