In a certain, corporate installation of Eclipse on a quite fast computer CRTL+Left click on java classes, members and methods in the java editor incurred always several seconds of a locked up eclipse which coincided with moderate network traffic. When disconnecting the network the delay would magically vanish.
Pierre-Antoine Grégoire came up with the reason and the solution: Mylyn, which tries to look up SVN information on a remote network drive. The solution is to map Mylyn hyperlinking to an unused key combination:
Window->Editors->Text Editors->Hyperlinking
Task URLs (Textual Editors)
Tasks (Textual Editors)
George's Techblog 