src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/AbstractInstallAction/update
class AbstractInstallAction:	update(): void {
		this.enabled = false;
		if (this.extension && !this.extension.isBuiltin) {
			if (this.extension.state === ExtensionState.Uninstalled && this.extensionsWorkbenchService.canInstall(this.extension)) {
				this.enabled = true;
				this.updateLabel();
			}
		}
	}