Just to clarify, computation performed in ``SymbolClassification`` does **not** (directly) impact the editor responsiveness, because the computation is [carried out in a separate thread](https://github.com/scala-ide/scala-ide/blob/master/org.scala-ide.sdt.core/src/scala/tools/eclipse/semantichighlighting/Presenter.scala#L110) than the UI Thread. However, it is true that the more time it takes to classify the positions, the longer the user will have to (asynchronously) wait before actually seeing the colors in the editor.