boolean addDefaultReference(Program program, Address fromAddr, int opIndex, Address toAddr,
			RefType refType) {
		Command<Program> cmd =
			new AddMemRefCmd(fromAddr, toAddr, refType, SourceType.USER_DEFINED, opIndex, true);
		return tool.execute(cmd, program);
	}
Check a memory address and warn the user if it has an issue.

@param c parent component or null
@param mem program memory
@param addr address to check
@param refOffset offset from addr
@return addr to be used or null if user cancels
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/references/ReferencesPlugin.java