I enabled the groovy-eclipse-plugin to support development in build.gradle files. But every time I write '.' Eclipse is blocked, waits 5secs and then shows me the following error:

The 'Groovy Code Completions' proposal computer from the 'org.codehaus.groovy.eclipse.codeassist.completion' plug-in did not complete normally. The extension took too long to return the 'computeCompletionProposals()' operation.'

To avoid this message, disable the 'org.codehaus.groovy.eclipse.codeassist.completion' plug-in or disable the 'Groovy Content' category on the content assist preference page.

IntelliSense in .groovy files works fine and without delay.