Extended sessions on StencylWorks are not good at the moment for my computer or possibly your computer. I have a very serious report here that may link to this bug. I ran into the same error, though it didn't corrupt my game to my knowledge (it opened when I restarted it)...
java.lang.OutOfMemoryError
at sun.misc.Unsafe.allocateMemory(Native Method)
at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:99)
at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:288)
at apple.awt.OSXSurfaceData.getBufferOfSize(OSXSurfaceData.java:2180)
at apple.awt.OSXSurfaceData$DrawingQueue.<init>(OSXSurfaceData.java:1613)
at apple.awt.OSXSurfaceData.<init>(OSXSurfaceData.java:68)
at apple.awt.OSXSurfaceData.<init>(OSXSurfaceData.java:48)
at sun.awt.image.BufImgSurfaceData.<init>(BufImgSurfaceData.java:344)
at apple.awt.OSXOffScreenSurfaceData.<init>(OSXOffScreenSurfaceData.java:610)
at apple.awt.OSXOffScreenSurfaceData.createDataIC(OSXOffScreenSurfaceData.java:494)
at apple.awt.OSXOffScreenSurfaceData.createDataIC(OSXOffScreenSurfaceData.java:515)
at apple.awt.OSXOffScreenSurfaceData.createNewSurface(OSXOffScreenSurfaceData.java:148)
at apple.awt.OSXOffScreenSurfaceData.createData(OSXOffScreenSurfaceData.java:109)
at sun.awt.image.BufImgSurfaceData.createData(BufImgSurfaceData.java:61)
at apple.awt.CGraphicsEnvironment.createGraphics(CGraphicsEnvironment.java:316)
at java.awt.image.BufferedImage.createGraphics(BufferedImage.java:1159)
at stencyl.sw.util.gfx.GraphicsUtilities.createThumbnail(GraphicsUtilities.java:451)
at stencyl.sw.editors.actor.appearance.AnimationListRenderer.getListCellRendererComponent(AnimationListRenderer.java:69)
at javax.swing.plaf.basic.BasicListUI.paintCell(BasicListUI.java:189)
at javax.swing.plaf.basic.BasicListUI.paint(BasicListUI.java:290)
at javax.swing.plaf.ComponentUI.update(ComponentUI.java:154)
at javax.swing.JComponent.paintComponent(JComponent.java:743)
at javax.swing.JComponent.paint(JComponent.java:1006)
at javax.swing.JComponent._paintImmediately(JComponent.java:4890)
at javax.swing.JComponent.paintImmediately(JComponent.java:4676)
at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:477)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:114)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
java.lang.OutOfMemoryError
at sun.misc.Unsafe.allocateMemory(Native Method)
at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:99)
at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:288)
at apple.awt.OSXSurfaceData.getBufferOfSize(OSXSurfaceData.java:2180)
at apple.awt.OSXSurfaceData$DrawingQueue.<init>(OSXSurfaceData.java:1613)
at apple.awt.OSXSurfaceData.<init>(OSXSurfaceData.java:68)
at apple.awt.OSXSurfaceData.<init>(OSXSurfaceData.java:48)
at sun.awt.image.BufImgSurfaceData.<init>(BufImgSurfaceData.java:344)
at apple.awt.OSXOffScreenSurfaceData.<init>(OSXOffScreenSurfaceData.java:610)
at apple.awt.OSXOffScreenSurfaceData.createDataIC(OSXOffScreenSurfaceData.java:494)
at apple.awt.OSXOffScreenSurfaceData.createDataIC(OSXOffScreenSurfaceData.java:515)
at apple.awt.OSXOffScreenSurfaceData.createNewSurface(OSXOffScreenSurfaceData.java:148)
at apple.awt.OSXOffScreenSurfaceData.createData(OSXOffScreenSurfaceData.java:109)
at sun.awt.image.BufImgSurfaceData.createData(BufImgSurfaceData.java:61)
at apple.awt.CGraphicsEnvironment.createGraphics(CGraphicsEnvironment.java:316)
at java.awt.image.BufferedImage.createGraphics(BufferedImage.java:1159)
at stencyl.sw.util.gfx.GraphicsUtilities.createThumbnail(GraphicsUtilities.java:451)
at stencyl.sw.editors.actor.appearance.AnimationListRenderer.getListCellRendererComponent(AnimationListRenderer.java:69)
at javax.swing.plaf.basic.BasicListUI.paintCell(BasicListUI.java:189)
at javax.swing.plaf.basic.BasicListUI.paint(BasicListUI.java:290)
at javax.swing.plaf.ComponentUI.update(ComponentUI.java:154)
at javax.swing.JComponent.paintComponent(JComponent.java:743)
at javax.swing.JComponent.paint(JComponent.java:1006)
at javax.swing.JComponent._paintImmediately(JComponent.java:4890)
at javax.swing.JComponent.paintImmediately(JComponent.java:4676)
at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:477)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:114)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
[LOG] Unexpected problem on thread AWT-EventQueue-0: null
Before the application actually crashed on me, the log file had gotten littered with Out of Memory errors, pretty much the same thing over and over again. To me... that is quite a lot for my computer. The log file itself is 22 MB, most of it Out of Memory errors. The first approx. 5 MB of it is perfectly normal, but beyond that, all heck breaks loose. The session lasted about an hour. It is the biggest log file that I have by far: the second-to-biggest log file is 2.1 MB from a month ago, and that doesn't have out of memory errors.