private int getLabelIndex(JLabel label) {
		for (int i = 0; i < operandLabels.length; i++) {
			if (operandLabels[i] == label) {
				return i;
			}
		}
		return ReferenceManager.MNEMONIC;
	}
Set the mnemonic text and attributes
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/references/InstructionPanel.java