button "add new source" doesn't work

[yedpodtrzitko]

steps to reproduce:

1) click add new source 2) enfill form's fields 3) submit via insert

expected result

• new source is added into combobox as another option

current result:

• created source is not added over there
• source's form is not reseted - filled values persist in form when you open it again

[mrpohoda]

Fixed in some previous commit - suddenly there was missing css class.