Symptoms
In K2 Smart Forms style margin not working for choice fields. Margins for dropdown are applied in designer but not in runtime. It seems that in runtime margin is applied not to the TextBox of the dropdown, but to the dropdown canvas with values.
Diagnoses
This is known issue in K2 4.6.9.
Resolution
As a workaround for this issue you may try to add a hidden data label on top of the choice control, then set the margins for both of those controls. Another option to try is to put an HTML literal control with a
statement but the absence of copy/paste functionality makes it too difficult to apply everywhere you may need it.