Improve the Errorhandling Usability for CreateDevice GUI

[mrentsch65]

When an error dialog occurs and is acknowledged, the main dialog disappears, which should not be the case for good usability.

[DorianSnowball]

the main dialog disappears,

Just to be clear: Which dialog disappears? The Dialog for the Device creation?

[mrentsch65]

Yes, the main plugin dialog. The plugin must be started again.

[DorianSnowball]

TODO: When an error occurs, the Plugin should stay on the CreateDevice GUI and not switch to the Start GUI