boolean hasLabelHistory(ListingActionContext context) {
		ProgramLocation location = context.getLocation();
		Address addr = null;
		if (location instanceof CodeUnitLocation) {
			CodeUnitLocation loc = (CodeUnitLocation) location;
			addr = loc.getAddress();
		}
		else if (location instanceof OperandFieldLocation) {
			Address a = location.getRefAddress();
			addr = (a == null) ? addr : a;
		}

		SymbolTable st = context.getProgram().getSymbolTable();
		return st.hasLabelHistory(addr);
	}
Return true if the given context has label history.

@param context the action context
@return true if the given context has label history
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/label/LabelMgrPlugin.java