I have shifted by Dev Env recently to Eclipse Helios on Windows 7. After that the Ctrl + Space Content Assist feature is not working. I found out that that key option is utilize
I found the answer. Windows / UV Elements - was OFF! I don't know how but they were off. And when you click Ctrl+Space he working, but your all elements are off and you think that it is not working. You must on all UV elements and after your Ctrl + Space will be work.
In Eclipse you can use the Alt-/ character sequense instead of Control-Space. This is an old problem which Eclipse and Chinese keyboards, which they addressed by adding this short cut.
!Screenshot of Eclipse Juno, I had the same problem, then I changed it to different key combination, then it works.1
This is what solved my problem.
Goto Control Panel -> Clock, Language and Region -> Change keyboards or other input methods -> Change keyboards... -> Advanced Key Settings. For some reason I had ctrl + space set as Key sequence for language hot keys. I changed them to something else and rebooted.
Make sure to reboot because it did not work for me without the reboot.
This is how I fixed my problem on Ubuntu 12.04 regardless of the eclipse version. My problem was that the ibus was overriding the shortcut so I deleted this shortcut configuration.
Type ibus in the dash:
Then select Keyboard Input Methods. From there click on the first three dots next to the Enable or disable textfield. This windows should appear:
If there is something bound to Ctrl + Space simply delete it.
I use eclipse indigo and had this problem. Creating a new workspace did not worked.
Go to Windows->preference->General->Keys->"Restore Default" - This fixed my issue
Note that I just had English(US) on windows 7 [Control Panel-> Clock,Language and Region ->Change keyboard or other input methods-> Keyboards and Languages->change Keyboards...->General ==>Default language is English and Installed Services I just had English(US) alone
After doing this some you might need to restart the system if it does not fix.