this bug has been reported several times but was either ignored or discarded.
I have the same bug and it is very annoying:
When using Cltr+Space on an unknown word and selection Add to dictionary the word is not added to the dictionary but the text 'Add "Unknown word"' is inserted in the text.
Replication of bug:
I tried a fresh installation to see how the bug can be replicated by anyone. System (Ubuntu 12.04 64-bit)
Download eclipse C++ from eclipse.org and install texlipse via marketplace.
OR Download eclipse classic from eclipse.org install the market place using install new software and then install texlipse via marketplace.
If I can provide anything which helps in removing this bug just give me a note.