I have been trying to look at Apple Interface Guidelines and Windows UX guidelines about what standard behavior for drop down menus in table cells should be. I can't find any mention of it. My specific questions are:
- Should the drop down always be visible or only appear when user clicks in a cell to edit it?
- Should it drop down on single click or on double click?
In e.g. Qt GUI toolkit the standard behavior is that cells with comboboxes look like regular text fields. When you click them to edit, you see the combobox and can click it. This means you always have to have a double click. In other applications I have seen that you always see the combobox and you only need a single click.
Perhaps there is no standard, but then what are the tradeoffs? When should you use one approach over another.
Edit: this is for a desktop application, so I'm not interested in best practices for webpages. I see a lot of the comments are related to web UIs.