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Hi,
The only one way to force wrap long titles I have found at the moment is to edit CUIX file manually in Text editor and insert special characters to the place where you need a line break.
For example:
You need to split "Drawing Setup" string in two lines. Than you need to extract RibbonRoot.cui file from your custom CUIX file, open RibbonRoot.cui in plain text editor application, find "Text" property of the button with name "Drawing Setup". It should look in the RibbonRoot.cui file something like this:
<RibbonCommandButton UID="RBNU_0077" Id="AcRibbonCommandButton" Text="Drawing Setup" ButtonStyle="LargeWithText" MenuMacroID="MMU_0032" KeyTip="">
<TooltipTitle xlate="true" UID="XLS_0002">Set DWG</TooltipTitle>
<ModifiedRev MajorVersion="21" MinorVersion="0" UserVersion="1" />
</RibbonCommandButton>
Now you need to insert special code - 
- between words "Drawing" and "Setup", now it should look like this:
<RibbonCommandButton UID="RBNU_0077" Id="AcRibbonCommandButton" Text="Drawing
Setup" ButtonStyle="LargeWithText" MenuMacroID="MMU_0032" KeyTip="">
<TooltipTitle xlate="true" UID="XLS_0002">Set DWG</TooltipTitle>
<ModifiedRev MajorVersion="21" MinorVersion="0" UserVersion="1" />
</RibbonCommandButton>
Than you need save RibbonRoot.cui file and replace old RibbonRoot.cui inside your CUIX file with this new version.
Now if you launch AutoCAD and look at your custom button, the text will be splitted into two lines. In CUI editor the "Name property of the button will show "DrawingSetup" without special characters.
Maxim