Multiple selections

hi, i am working at a parametric search form vith views and i use "multiple selections" for my fields. I have 4 types of options and finali a search button. All 4 of them are using multiple selection. I notice that once i click on a option and select that option there is no way to deselect, just to select another one. I could hold CTRL or CMD(mac) but i am afraid that other users don't know that. Is there any way tot deselect somthing once you select that option, like cikt to select and click to deselect?
The field name is multiple selection but without holding CTRL you can not select multiple options….