In order to "try" to rule out that the problem is hardware, I've just tried to boot my PC selecting the Windows partition. I noticed that also in Windows all external monitors work, except for the ACER CB282K. I tried to download Windows driver(s) for that monitor but I did not find anything so far. Can I do more tests in Windows to rule them out hardware issues? I wait for SUSE drivers or fixing bug but in the meantime I would like to rule out a problem given by the hardware.