ASP.NET DropDown List position is lost when user typing pauses
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One of my end-users just reported an odd problem in an ASP.NET 2.0 application, which I've confirmed, but which seems rather odd to me.  I have a DropDownList control on my web form, which displays several dozen different items.  The easiest method for them to navigate the list is by typing the first several letters of the item they want to select.  No problem, and we're all familiar with this approach.

The issue arises when they pause typing, wait a second or so (to consult a document for a serial number, for example), and then resume typing the next letters of their target selection.  As soon as they resume typing, the position they had in the list is ignored, and the cursor moves to the value which begins with the new sequence of characters they have keyed in.  For example, if they are trying to select a value of "PREAMBLE", and they type the letters PRE, the first item containing "PRE" is highlighted.  However, if they pause for a moment, then continue with "AMBL", the list jumps back to the beginning, and the first list item containing "AMBL" is highlighted.  Since the users are typing serial numbers in one of the dropdowns, this habit of pausing for a moment is completely natural, but it also causes them some frustration, as they have to type in a longer string of characters without stopping.

I've tested this on Chrome and Internet Explorer and Firefox, so I conclude it isn't browser specific.  Is there a time paramater I can adjust on the dropdown list, to allow for a longer pause?  Is there a way to disable the behavior I've described here?  I can duplicate the behavior on a list with as few as seven items.  On a list of seven items, it isn't a problem, but on a list with a hundred items, it gets to be a hassle.

Any insight in to this would be most appreciate, as would any suggestions on how to avoid it from happening, especially if I can disable it on a control by control basis.  Thanks in advance!