The IR file browser control is instantiated with kMsgTagClearModel as its mClearMsgTag:
https://github.com/sdatkinson/NeuralAmpModelerPlugin/blob/cb0132011598d5597fc56fd7218795bfc725bbc9/NeuralAmpModeler/NeuralAmpModeler.cpp#L204C26-L204C26

Instead, it should be kMsgTagClearIR:
https://github.com/sdatkinson/NeuralAmpModelerPlugin/blob/cb0132011598d5597fc56fd7218795bfc725bbc9/NeuralAmpModeler/NeuralAmpModeler.cpp#L431C10-L431C24