not able to select tools in DMU kinematics and wireframe and surface design workbenches

after looking at your screen shoot i have come to two conclusion for your problem......first pls select the part properly u want to apply the operation and second if this problem remains pls reinstall your software

I actually got soln . I have mistakenly change small scale in option which I corrected by changing it to standard scale. By the way thanks for answering.

well thts good to kmow....;)
keep asking question about your doubts...;)

You can find the tutorial for that in the link below:

https://www.udemy.com/catia-v5-dmu-kinematic/?couponCode=GREEDISGOOD