Bug 180758 [IDE] Deleting a project but not the contents asks if you want to delete read-only files
I have noticed that in 3.3M6, if I delete a project that has read-only files in it, it will prompt if I want to delete the files even if I select "Do not delete contents". The files are not actually deleted, but the error dialog should not be presented to the user since the files are not actually being deleted. I don't remember seeing this in 3.3M4 or earlier.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/DeleteResourceAction.java
protected boolean updateSelection(IStructuredSelection selection) {
		return super.updateSelection(selection)
				&& canDelete(getSelectedResourcesArray());
	}
	/**
	 * Returns the model provider ids that are known to the client that
	 * instantiated this operation.
	 * 
	 * @return the model provider ids that are known to the client that
	 *         instantiated this operation.
	 * @since 3.2
	 */
	public String[] getModelProviderIds() {
		return modelProviderIds;
	}
	/**
	 * Sets the model provider ids that are known to the client that
	 * instantiated this operation. Any potential side effects reported by these
	 * models during validation will be ignored.
	 * 
	 * @param modelProviderIds
	 *            the model providers known to the client who is using this
	 *            operation.
	 * @since 3.2
	 */
	public void setModelProviderIds(String[] modelProviderIds) {
		this.modelProviderIds = modelProviderIds;
	}
}