Bug 219901 [Undo] new file creation subjec to Undo (file deleted without warning)
when creating a new file by right clicking on your project in the project explorer new->file this action is put on the undo/redo stack. Pressing Ctrl-Z to undo this action will thus delete your file. As this stack is separate from the stack in the editor , one can create a new file, work for a long time, then inadvertently press ctrl-z to undo a code change while having the focus on the project explorer and irrevocably lose their file. Redo will create a new EMPTY file; the work is gone, forever. This appears to only work for the "new file", not for "new->source file" etc. Although some may perceive this as a feature, it is hard to imagine a scenario where ctrl-z should permanently delete a file without warning.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/dialogs/WizardNewFileCreationPage.java
setMessage(null);
			setErrorMessage(null);
			
			
			if (resourceGroup.getAllowExistingResources()) {
				String problemMessage = NLS.bind(IDEWorkbenchMessages.ResourceGroup_nameExists, getFileName());
				IPath resourcePath = getContainerFullPath().append(getFileName());
				if (workspace.getRoot().getFolder(resourcePath).exists()) {
					setErrorMessage(problemMessage);
					valid = false;
				}
				if (workspace.getRoot().getFile(resourcePath).exists()) {
					setMessage(problemMessage, IMessageProvider.WARNING);
				}
			}
		}
		return valid;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.dialogs.DialogPage#setVisible(boolean)
	 */
	public void setVisible(boolean visible) {
		super.setVisible(visible);
		if (visible) {
			resourceGroup.setFocus();
		}
	}
}