See https://groups.google.com/d/topic/scala-ide-user/Q1tytYaqRoY/discussion
{...} can be replaced with () as long as it contains only one expression (not multiple statements).
(...) can be replaced with {} as long as it contains only one expression (not multiple arguments, nor tuples).

This is particularly useful when choosing a code completion. For example, when choosing `map`, the IDE will insert `{ x => ??? }`, but in some cases it makes more sense to use round parenthesis. It would be great to have a simple way to switch between the two. This could be an editor action that automatically changes the matching parenthesis, using linked-mode editing. Some example code using linked-mode editing already exists in code completion, in mkLinkedModeModel.
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