ComboBox - dhtmlXComboFromSelect - error in width

I use dhtmlXComboFromSelect for create select-element in bootstrapModa. After load modal is hide, and open after user action.
So - in my case - with is not correct (my width set in html - style=‘width:350px;’). I think because - in hidden state offsetWith is 0px.

How I can fix this?

Unfortunately the only solution is to initialize your combo only when the your select is not hidden.