src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/SetFileIconThemeAction/update
class SetFileIconThemeAction:	update(): void {
		this.enabled = !!this.extension && (this.extension.state === ExtensionState.Installed) && this.fileIconThemes.some(th => isThemeFromExtension(th, this.extension));
		this.class = this.enabled ? SetFileIconThemeAction.EnabledClass : SetFileIconThemeAction.DisabledClass;
	}