Bug 29698 drag and drop of java files between packages in package explorer doesn't work
the <preview> <ok> <cancel> dialog shows up, but <ok> has the same effect as <cancel> and <preview> would only show movements of files and no changes in imports of other java files. on <ok> in the preview it only moves the file(s) (as indicated ) without changing referencing imports.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/reorg/JdtMoveAction.java
fRefactoring.getUpdateQualifiedNames() && fRefactoring.canEnableQualifiedNameUpdating() ||
						fReferenceCheckbox.getSelection() && fRefactoring.canUpdateReferences();
				fPreview.setEnabled(preview);
			} catch (JavaModelException e){
				ExceptionHandler.handle(e, ReorgMessages.getString("JdtMoveAction.move"), ReorgMessages.getString("JdtMoveAction.exception")); 
			}		
		}
		protected void buttonPressed(int buttonId) {
			fShowPreview= (buttonId == PREVIEW_ID);
			super.buttonPressed(buttonId);
			if (buttonId == PREVIEW_ID)
				close();
		}
		
		protected void configureShell(Shell newShell) {
			super.configureShell(newShell);
			WorkbenchHelp.setHelp(newShell, IJavaHelpContextIds.MOVE_DESTINATION_DIALOG);
		}
		protected void createButtonsForButtonBar(Composite parent) {
			fPreview= createButton(parent, PREVIEW_ID, ReorgMessages.getString("JdtMoveAction.preview"), false); 
			super.createButtonsForButtonBar(parent);
		}
		
		protected Control createDialogArea(Composite parent) {
			Composite result= (Composite)super.createDialogArea(parent);
			addUpdateReferenceComponent(result);
			addUpdateQualifiedNameComponent(result, ((GridLayout)result.getLayout()).marginWidth);
			return result;
		}
		private void addUpdateReferenceComponent(Composite result) {