here i saw this yesterday on the autodesk support site danreese
"Issue
You want to set a default button for a flyout on a toolbar.
A flyout is a set of buttons nested under a single button on a toolbar. The button that displays a flyout, has a black triangle in the lower-right corner. When you start AutoCAD 2000, each flyout displays a default button on its associated toolbar. For example, on the Standard Toolbar the default button for the Zoom flyout, is Zoom Window. During an AutoCAD session, the flyout button displayed on the toolbar, is the last button you used on the flyout.
You can change the behavior of a flyout so that it persistently displays the same button on the toolbar. That is, the same flyout button displays when AutoCAD starts, and during the AutoCAD session.
Solution
This solution provides an example of setting a default button for the Zoom flyout on the Standard Toolbar.
Procedure:
Choose the button that you want as the default button from the Zoom flyout on the Standard Toolbar. This action starts the command for that button. Cancel the command. The selected button is now displayed on the Standard Toolbar.
Right-click on the button for the Zoom Flyout on the Standard Toolbar, and choose Customize from the shortcut menu. AutoCAD displays the Toolbars dialog box.
Right-click the same button that you right-clicked in the previous step.
In the Flyout Properties dialog box, select an icon from the list in the Button Icon area.
Note: Although you can select any button icon in step 4, we suggest that you select the icon associated with the command. That's because no matter what button icon you select, the command is that of the button you right-clicked in steps 2 and 3. For example, it's illogical to use the diskette button icon (save), if the command for the button is Zoom Extents.
Select the option Show this Button's Icon, then choose Apply.
Close the Flyout Properties dialog box, and the Toolbars dialog box.
After completing the procedure, the flyout:
persistently displays the same button on the toolbar.
runs the command for the button when you select it. The command is that of the button you right-clicked in steps 2 and 3."
i hope this helps also look at your MNS/MNU file if you have save custom bmp files for icons if you specify the actual name in the MNS/MNU file you are less likely to get smilies or incorrect buttom images
if everyone helps everybody the world will be a better place