I've looked back and my understanding is that you are running Kubuntu 24. Which window manager are you using under Kubuntu? Is it Wayland and X11? If you are running with Wayland, for diagnostic purposes, could you please try the X11 window manager to see if it corrects the problem?
Hello Karen
The window manager is X11. I'll try to change it, but I'm far away to understand how to.
I get this message when I open the Measurement.csv file with AIJ ; there is an exception at the begining, that perhaps make sense to you.
Fred
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AIJ 5.4.0.00; ImageJ 1.54m1; Java 23.0.1 [64-bit]; Linux 6.8.0-51-generic; 31MB of 23408MB (<1%)
java.lang.NullPointerException: Cannot invoke "java.awt.Color.equals(Object)" because the return value of "javax.swing.JRadioButton.getBackground()" is null
at Astronomy.MultiPlot_.lambda$constructOtherGroup$285(MultiPlot_.java:11950)
at java.desktop/javax.swing.JComboBox.fireActionEvent(Unknown Source)
at java.desktop/javax.swing.JComboBox.setSelectedItem(Unknown Source)
at Astronomy.MultiPlot_.updateGUI(MultiPlot_.java:15869)
at Astronomy.MultiPlot_.showMoreCurvesJPanel(MultiPlot_.java:11160)
at Astronomy.MultiPlot_.showMainJPanel(MultiPlot_.java:11078)
at Astronomy.MultiPlot_.finishSetup(MultiPlot_.java:1191)
at Astronomy.MultiPlot_.setTable(MultiPlot_.java:1177)
at Astronomy.MultiPlot_.setTable(MultiPlot_.java:1145)
at Astronomy.MultiPlot_.findTables(MultiPlot_.java:1113)
at Astronomy.MultiPlot_.run(MultiPlot_.java:1084)
at util.AIJStartupHandler.lambda$static$0(AIJStartupHandler.java:47)
at ij.astro.util.FileAssociationHandler$AssociationMapper.open(FileAssociationHandler.java:86)
at ij.astro.util.FileAssociationHandler.handleFile(FileAssociationHandler.java:33)
at ij.astro.util.FileAssociationHandler.handleFile(FileAssociationHandler.java:22)
at ij.io.Opener.open(Opener.java:114)
at ij.io.Opener.open(Opener.java:98)
at ij.plugin.Commands.run(Commands.java:32)
at ij.IJ.runPlugIn(IJ.java:216)
at ij.Executer.runCommand(Executer.java:156)
at ij.Executer.run(Executer.java:74)
at java.base/java.lang.Thread.run(Unknown Source)
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As for this exception, it seems like the preferences file has gotten into a bad state. We'll have to work on a proper fix, but you should be able to resolve it by resetting your preferences via Multiplot's main window.