我想知道是否有人可以详细说明以下错误而无需发布我的整个代码。我有一个绘制图像的对象和一个在顶部绘制另一个图像的线程对象。每当通过单击并拖动鼠标更改图像可见区域时，我有时会收到此错误，并且我的应用程序会冻结。
java.lang.InternalError: Unrecognized PGCanvas token: 68
at com.sun.javafx.sg.prism.NGCanvas.renderStream(NGCanvas.java:699)
at com.sun.javafx.sg.prism.NGCanvas.renderContent(NGCanvas.java:339)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:187)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:39)
at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1145)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:204)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:420)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:187)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:39)
at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1145)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:204)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:420)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:187)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:39)
at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1145)
at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:117)
at com.sun.javafx.tk.quantum.AbstractPainter.paintImpl(AbstractPainter.java:181)
at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:73)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(Unknown Source)
at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at com.sun.prism.render.RenderJob.run(RenderJob.java:37)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:104)
at java.lang.Thread.run(Unknown Source)
java.lang.InternalError: Unrecognized PGCanvas token: 68