private void setStale(boolean stale) {
		if (stale) {
			refreshAction.getToolBarData().setIcon(REFRESH_ICON);
		}
		else {
			refreshAction.getToolBarData().setIcon(REFRESH_NOT_NEEDED_ICON);
		}
	}
NB: This is key as well.

this is called in the doSetFunction method
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/plugin/core/decompiler/taint/TaintSliceTreeProvider.java