Hi Atick,
I made a discovery concerning the flaw explaned above:
When trying to enter values for padding or margin for a phone landscape, no entry is accepted.
I found out, that this only happens, if there has been no values entered previously for the laptop settings.
When I only enter one character for laptop, it is possible to enter values for phone landscape from this moment on.
Maybe this will help you to find the bug.
Also after working with the front end editor for a few days, suddenly it does not show any website contents anymore