• I have tested the latest master version from http://builds.jabref.org/master/ and the problem persists

JabRef 4.2-dev--snapshot--2018-01-04--master--1b06811df
Windows 10 10.0 amd64
Java 1.8.0_151

Steps to reproduce:

1. Start JabRef
2. Open two databases
3. Select and open one entry for editing in first database
4. Click to open DOI or URL in browser
5. Select and open second entry for editing or preview in first database
6. Select and open third entry--will see a blank entry editor and preview
7. Select second database
8. Repeat Some example new Dutch translations via the GitHub web page. #3-6 - entry editor shows fine until same routine as above (click to view URL/DOI, next entry shows, then blank for third.

Log file included, but does not seem to be repeated for each time this issue arises.

Log File

```Opening: DOAJ-WaterGov-MLG-Indig-Eng.bib Opening: Wiley-WaterGov-Indig-Eng.bib Uncaught exception occurred in Thread[JavaFX Application Thread,5,main] java.lang.IndexOutOfBoundsException: [-2147483648, 21) is not a valid range within [0, 21) at org.reactfx.util.Lists.checkRange(Lists.java:128) at org.reactfx.util.Lists.checkRange(Lists.java:123) at org.reactfx.collection.MemoizationListImpl.forget(MemoizationList.java:184) at org.fxmisc.flowless.CellListManager.cropTo(CellListManager.java:82) at org.fxmisc.flowless.CellPositioner.cropTo(CellPositioner.java:29) at org.fxmisc.flowless.Navigator.cropToNeighborhoodOf(Navigator.java:227) at org.fxmisc.flowless.Navigator.placeStartAtMayCrop(Navigator.java:200) at org.fxmisc.flowless.Navigator.visit(Navigator.java:129) at org.fxmisc.flowless.StartOffStart.accept(TargetPosition.java:85) at org.fxmisc.flowless.Navigator.layoutChildren(Navigator.java:78) at javafx.scene.Parent.layout(Parent.java:1087) at org.fxmisc.flowless.VirtualFlow.layoutChildren(VirtualFlow.java:257) at javafx.scene.Parent.layout(Parent.java:1087) at javafx.scene.Parent.layout(Parent.java:1093) at javafx.scene.Parent.layout(Parent.java:1093) at javafx.scene.Parent.layout(Parent.java:1093) at javafx.scene.Parent.layout(Parent.java:1093) at javafx.scene.Scene.doLayoutPass(Scene.java:552) at javafx.scene.Scene.preferredSize(Scene.java:1646) at javafx.scene.Scene.impl_preferredSize(Scene.java:1720) at javafx.stage.Window$9.invalidated(Window.java:846) at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:109) at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:144) at javafx.stage.Window.setShowing(Window.java:922) at javafx.stage.Window.show(Window.java:937) at com.sun.javafx.stage.EmbeddedWindow.show(EmbeddedWindow.java:58) at javafx.embed.swing.JFXPanel.lambda$addNotify$49(JFXPanel.java:799) at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295) at java.security.AccessController.doPrivileged(Native Method) at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294) at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177) at java.lang.Thread.run(Unknown Source) ```

[Blank](https://user-images.githubusercontent.com/23559478/34622024-0fb5c11e-f211-11e7-82e3-4e732987f7d7.png)