I've been meaning to post this but have been busy and just realized that I forgot about it. In searching around for solutions to various issues in the project I'm working on I came across this which is a very workable solution to the problem of long module names in the control panel dropdown list. I hope it is usefull.

My apologies to the author but he didn't include a signature in the post so when I saved it his name was not included. I can't remember where I found it and went looking but couldn't find it again. There are actually two CSS style changes you need to make. One for the standard DNN Administrator's Control Panel which is the one that was included in the post I found. The changes for the Smart-Thinker Control panel I found by looking at the source.

*** This changes the standard DNN Control panel ***
.ControlPanel SELECT.NormalTextBox, .ControlPanel INPUT.NormalTextBox
{
width:250 !important;
}

*** This is for the Smart-Thinker Control Panel ***
.ControlPanelStyle SELECT.NormalTextBox, .ControlPanelStyle INPUT.NormalTextBox
{
width:200 !important;
}

To try it out just put these entries into your portal.css using the Administrator Site Setting to edit the css styles. Remember, you will have to do a [CTRL-F5] (in I.E.) to force a reload of the stylesheet.

I hope this post comes out formatted in a readable fassion. I've had problems where it all just gets put together in a single string of text so I'm attempting to enter this using straight test and HTML tags. Enjoy!!!!

an other approache

Go to  ~\admin\ControlPanel and open up the iconbar.ascx file.
Using Ctrl F find for cboDesktopModules.

This will bring u to the following line :
<asp:dropdownlist id="cboDesktopModules" runat="server" cssclass="NormalTextBox" Width="140" datavaluefield="DesktopModuleID" datatextfield="FriendlyName"/>

Change the Width for your needs.
Save and Refresh Page.