I'm using the ComboBox with a checkbox list. The normal behavior for this control is to display the individual items that have been checked in the combobox "header" until the items exceed the width of the control. When that happens the item list that displays in the header is replaced by a generic "x items checked".
I can select/check various items, click away from the combobox, and the autopostback is triggered. I can then check other items, click away from the combobox again, and again the autopostback is triggered. Works great.
But if I check, say, 6 items the first time (the header reads "6 items checked"), which triggers the autopostback when I click away and then check a different set of 6 items (the header still reads "6 items checked"), then the autopostback doesn't fire. I can continue selecting different sets of 6 items and the autopostback is never triggered. As soon as I select 5 items or 7 items (anything but 6 items), then the autopostback is triggered.
This appears to only be an issue when the generic "x items checked" message is showing, no matter the number. If I check only two items that do fit in the header and then select a different two items after the first postback, it works as expected.
Here's how the combo box is defined:
<telerik:RadComboBox id="ddlSpeciality" runat="server" Width="250px"
CheckBoxes="true" EnableCheckAllItemsCheckBox="true" OnClientItemChecking="OnClientItemChecking2"
The combobox items are loaded dynamically when the page is loaded. The OnClientItemChecking is only required because we use some item grouping and the client function selects/deselects all items in any particular grouping when the parent item is checked/unchecked. This does not seem to have any bearing on the problem I described above as I can recreate the problem using only top level items with no grouping.