Hello Paulo,
This issue is fixed with C1TrueDBGrid build 61336.
Please download the build from below links:
http://prerelease.componentone.com/dotnet20/c1truedbgrid/2013-t3/C1TrueDBGrid.2_2.0.20133.61336.zip
http://prerelease.componentone.com/dotnet40/c1truedbgrid/2013-t3/C1TrueDBGrid.4_4.0.20133.61336.zip
Regards,
Reema