my Pleco version is 3.2.12 (as it written in Settings section). Regarding the deleting - I have deleted it from "Installed Add-ons" section, and not from "Manage Dictionaries" section, where indeed it was impossible to delete. Yes, even in "fool-proof" program, fools can always surprise.
Thank you Mike, but the problem is solved-
I succeeded to transfer the relevant CC dict. file from my other android device, where Pleco is also installed.
(I study via Pleco both on my smartphone and android emulation on my PC)
Thank you very much.