boolean canClose() {
		for (Plugin p : pluginList) {
			if (!p.canClose()) {
				return false;
			}
		}
		return true;
	}
Called to force plugins to terminate any tasks they has running and
apply any unsaved data to domain objects or files. If they can't do
this or the user cancels then this returns false.
@return true if all the plugins indicated they can close.
Ghidra/Framework/Project/src/main/java/ghidra/framework/plugintool/PluginManager.java