combobox gets narrower

My comboboxes are special. Allways when the down arrow in a combox is clicked to choose an item the width of that combobox gets narrower. Click by click it gets as narrow as the TextField on the first row - maybe 1 or 2 millimeters narrower.

Conboboxes are created like this:

setItemDataSource(new BeanItem(pojo_DataModel));

		getField("lkm").setDescription("Osumien määrä");

		// alkuarvot valikoihin
		for (int i = 1; i < order.length; i++) {
			comboItems = hakuLauseVaadin.alkuarvotComboboxiin(order[i]
, comboItems, comboItems)

		for (int i = 1; i < order.length; i++) {
					"Valitse " + ohje[i]
 + ". Ei ole pakollinen.");


I suppose you’re experiencing this issue only in Firefox 3+, right?

A recuded test case would be greatly appreciated, it would speed up fixing the issue.

It is ok with Safari 4.0.4 and Opera 10.10 in MacBook.