Bug 53742 [templates] add different ui for linked mode depending on usage
Linked mode should allow to be configured programmatically to have a different ui. This would allow the instance that is setting up linked mode to determine how it will look like. Use case is auto-closing: the box is too disturbing there, while it may be good for more complex templates.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
if (startOffset == -1) {
					startOffset= endOffset; 
					revealStartOffset= revealEndOffset;
				}
				
				if (endOffset == -1) {
					endOffset= startOffset; 
					revealEndOffset= revealStartOffset;
				}
				
				IJavaElement element;
				if (endOffset == -1) {
					 
					element= fEndOffset.getElement();
					if (element == null)
						element= fStartOffset.getElement();
					if (element != null)
						setSelection(element);
					return;
				}
							
				if (isValidSelection(revealStartOffset, revealEndOffset - revealStartOffset) && isValidSelection(startOffset, endOffset - startOffset))
					selectAndReveal(startOffset, endOffset - startOffset, revealStartOffset, revealEndOffset - revealStartOffset);
			} finally {
				fStartOffset.clear();
				fEndOffset.clear();
			}
		}
		private boolean isValidSelection(int offset, int length) {