RS if deleted wiki file has no extension

2015-03-30 14:57:06,063 [ajp-bio-8006-exec-996] ERROR Window - OLAT::ERROR ^%^ N1-E2109 ^%^ org.olat.core.gui.components 
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0 

**RedScreen** exception while rendering component 'table' (org.olat.core.gui.components.table.Table) listener:[org.olat.core.gui.components.table.TableController [cListener:org.olat.modules.wiki.WikiMainController, ]]
Message of exception: String index out of range: -1 

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: exception while rendering component 'table' (org.olat.core.gui.components.table.Table) listener:[org.olat.core.gui.components.table.TableController [cListener:org.olat.modules.wiki.WikiMainController, ]]
Message of exception: String index out of range: -1
-> at org.olat.core.gui.components.Window.dispatchRequest(Window.java:756)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:228)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:192)
   at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:241)
   at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:197)
   at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:269)
   at org.olat.core.servlets.OpenOLATServlet.doGet(OpenOLATServlet.java:198)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
   at org.olat.core.servlets.OpenOLATServlet.service(OpenOLATServlet.java:155)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
>>> stack of 2.cause::java.lang.StringIndexOutOfBoundsException: String index out of range: -1
-> at java.lang.String.substring(String.java:1954)
   at org.olat.modules.wiki.MediaFilesTableModel$StrikeThroughCellRenderer.render(MediaFilesTableModel.java:122)
   at org.olat.core.gui.components.table.CustomRenderColumnDescriptor.renderValue(CustomRenderColumnDescriptor.java:60)
   at org.olat.core.gui.components.table.TableRenderer.appendSingleDataRow(TableRenderer.java:295)
   at org.olat.core.gui.components.table.TableRenderer.appendDataRows(TableRenderer.java:268)
   at org.olat.core.gui.components.table.TableRenderer.render(TableRenderer.java:108)
   at org.olat.core.gui.render.Renderer.render(Renderer.java:236)
   at org.olat.core.gui.render.Renderer.render(Renderer.java:186)
   at org.olat.core.gui.render.velocity.VelocityRenderDecorator.doRender(VelocityRenderDecorator.java:639)
   at org.olat.core.gui.render.velocity.VelocityRenderDecorator.render(VelocityRenderDecorator.java:442)
   at sun.reflect.GeneratedMethodAccessor234.invoke(Unknown Source)