Crash on UI Export

[KRN-8]

in "UI Edditor" put stuff in or leave empty > press "$export" > Crashes

Crash log:

Version: steam build 126.3
OS: Windows 10 x64
Java Version: 1.8.0_72
Java Architecture: 64

rhino.EcmaError: TypeError: Cannot read property "text" from undefined (elements#31)
	at rhino.ScriptRuntime.constructError(ScriptRuntime.java:3955)
	at rhino.ScriptRuntime.constructError(ScriptRuntime.java:3935)
	at rhino.ScriptRuntime.typeError(ScriptRuntime.java:3964)
	at rhino.ScriptRuntime.typeError2(ScriptRuntime.java:3980)
	at rhino.ScriptRuntime.undefReadError(ScriptRuntime.java:3990)
	at rhino.ScriptRuntime.getObjectElem(ScriptRuntime.java:1403)
	at rhino.gen.elements_63._c_anonymous_2(elements:31)
	at rhino.gen.elements_63.call(elements)
	at rhino.ArrowFunction.call(ArrowFunction.java:33)
	at rhino.optimizer.OptRuntime.call1(OptRuntime.java:23)
	at rhino.gen.uieditor_62._c_anonymous_1(uieditor:32)
	at rhino.gen.uieditor_62.call(uieditor)
	at rhino.ArrowFunction.call(ArrowFunction.java:33)
	at rhino.optimizer.OptRuntime.callProp0(OptRuntime.java:71)
	at rhino.gen.uieditor_62._c_anonymous_19(uieditor:200)
	at rhino.gen.uieditor_62.call(uieditor)
	at rhino.ContextFactory.doTopCall(ContextFactory.java:346)
	at rhino.ScriptRuntime.doTopCall(ScriptRuntime.java:3303)
	at rhino.gen.uieditor_62.call(uieditor)
	at rhino.ArrowFunction.call(ArrowFunction.java:33)
	at rhino.InterfaceAdapter.invokeImpl(InterfaceAdapter.java:141)
	at rhino.InterfaceAdapter.lambda$invoke$0(InterfaceAdapter.java:92)
	at rhino.Context.call(Context.java:524)
	at rhino.ContextFactory.call(ContextFactory.java:446)
	at rhino.InterfaceAdapter.invoke(InterfaceAdapter.java:92)
	at rhino.jdk18.VMBridge_jdk18.lambda$newInterfaceProxy$0(VMBridge_jdk18.java:100)
	at com.sun.proxy.$Proxy2.run(Unknown Source)
	at arc.scene.Element.lambda$clicked$2(Element.java:893)
	at arc.scene.Element$4.clicked(Element.java:902)
	at arc.scene.event.ClickListener.touchUp(ClickListener.java:77)
	at arc.scene.event.InputListener.handle(InputListener.java:31)
	at arc.scene.Scene.touchUp(Scene.java:360)
	at arc.input.InputMultiplexer.touchUp(InputMultiplexer.java:137)
	at arc.input.InputEventQueue.drain(InputEventQueue.java:71)
	at arc.backend.sdl.SdlInput.update(SdlInput.java:102)
	at arc.backend.sdl.SdlApplication.loop(SdlApplication.java:145)
	at arc.backend.sdl.SdlApplication.<init>(SdlApplication.java:44)
	at mindustry.desktop.DesktopLauncher.main(DesktopLauncher.java:36)