Bug 33389 Read-Only files: Quick fix enabled and gets checkmark!
RC1 1. set a file to ready only. 2. Open the file an set the cursor inside 3. Open the 'Edit' menu. Note that 'Quick fix' is enabled, but 'Content assist' is not 4. Choose 'Quick fix' 5. Open the context menu: Quick fix got a checkmark!
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
public void setCloseStringsEnabled(boolean enabled) {
			fCloseStrings= enabled;
		}
		private boolean hasIdentifierToTheRight(IDocument document, int offset) {
			try {
				int end= offset;
				IRegion endLine= document.getLineInformationOfOffset(end);
				int maxEnd= endLine.getOffset() + endLine.getLength();
				while (end != maxEnd && Character.isWhitespace(document.getChar(end)))
					++end;
				return end != maxEnd && Character.isJavaIdentifierPart(document.getChar(end));
			} catch (BadLocationException e) {
				
				return true;
			}
		}
		private boolean hasIdentifierToTheLeft(IDocument document, int offset) {
			try {
				int start= offset;
				IRegion startLine= document.getLineInformationOfOffset(start);
				int minStart= startLine.getOffset();
				while (start != minStart && Character.isWhitespace(document.getChar(start - 1)))
					--start;
				
				return start != minStart && Character.isJavaIdentifierPart(document.getChar(start - 1));
			} catch (BadLocationException e) {
				return true;
			}			
		}
		private boolean hasCharacterToTheRight(IDocument document, int offset, char character) {