Supported Eclipse Client versions
One answer
This document http://www-03.ibm.com/software/products/en/rtc provides a lot of detail. Looking in "Prerequisites", "Eclipse Runtime Environment" for CLM 4.0.6 I see that 3.6.2, 3.7.2 and 4.2.2 are the minimum required.
This is further confirmed by https://jazz.net/wiki/bin/view/Deployment/CLMSystemRequirements405406#B4_Eclipse_IDE_RTC_Eclipse_Clien which mentions 3.6.2.3, 3.7.2 and 4.2.2.1
This is further confirmed by https://jazz.net/wiki/bin/view/Deployment/CLMSystemRequirements405406#B4_Eclipse_IDE_RTC_Eclipse_Clien which mentions 3.6.2.3, 3.7.2 and 4.2.2.1