Sounds like you may be positioning the menu absolutely instead of relatively.
Open up your udm-custom.js file and look for this section:
Code:
//navbar orientation
um.orientation = [
"vertical", // alignment ["vertical"|"horizontal"|"popup"|"expanding"]
"left", // h align ["left"|"right"]
"top", // v align ["top"|"bottom"]
"absolute", // positioning ["relative"|"absolute"|"fixed"|"allfixed"]
"0.5em", // x position ["em"|"ex"|"px"|"0"]
"0.5em", // y position ["em"|"ex"|"px"|"0"]
"1000", // z order ["0" to "10000"] (menu takes 20000 headroom)
];
Change the "absolute" to "relative"
You may also want to check out these demos:
http://www.udm4.com/demos/vertical-r...left-table.php
and
http://www.udm4.com/demos/horizontal...left-table.php