Window is moved instead of moving camera when click/drag on the 3D View
There is an issue on Kutuntu 18.04 with default settings and ParaView master related to the new QVTKWidget/OpenGLWindow. When trying to interacting in the 3D Render view with the left button, instead of moving the camera view point, the whole window is moved instead - very frustrating.
After digging a bit in the problem it appears that the problem appears with the default Application Widget style "Breeze" in which the setting "Window's drag mode" is set to "Drag windows from all empty areas". Changing this option to "Draw windows from title bar only" solve the issue. But it certainly means that there are some events that are not correctly handled in the event management of the new widget or window.