Yes I am aware of this issue. It happens also in the blog module when a user clicks the calendar. My recommendation is to avoid postback in the ModuleControl and link to edit pages instead and do postback there as needed. I would like to eliminate the postback in the blog module control as well. The Module Control is just the entry point to a feature and it can be on a page with other module controls so when it does postback it can cause unexpected side effects for other modules that might be on the same page. For example some module have if(!IsPostBack){ PopulateControls();}, if another module causes the page to post back modules that have this code disappear from the page. Also modules that use postback can't be cached without breaking the functionality.

Another alternative might be to wrap a MagicAjax Panel around the controls in your module which will make it do an ajax partial postback instead of posting back the entire page

<ajax:AjaxPanel id="pnlMyModule" runat="server">
your controls go here

</ajax:AjaxPanel>

This might be a more elegant solution, though I really haven't tried it in a module control yet I think it should work.

Hope it helps,

Joe