Question

This is a much simpler question.

private static AplotBaseDialog dlg; 


public Object execute(final ExecutionEvent event) throws ExecutionException {
  if (dlg == null){
     try {
          Shell shell = HandlerUtil.getActiveWorkbenchWindowChecked(event).getShell();
          dlg = new AplotBaseDialog(shell, session);  
     }
     catch {
     }
     dlg.open();
     return null;
 }

Ok the above code checks and see if dlg is null. If it is null then create a new dialog.
Then it opens the dialog.

This works when dlg is null. But if dlg is not null, I get a error at the line dlg.open().
The error is pointing to this code in the dialog class

  @Override
  protected Control createContents(Composite parent) {
     Control contents = super.createContents(parent); <==== Right Here
     setTitle("Title");
     setMessage("Message");
     if (image != null) {
        setTitleImage(image);
     }
     return contents;
  }

So my question is how can I open the dialog when dlg != null?

EDIT
Adding some of the error message

line 110 in AplotBaseDialog

Control contents = super.createContents(parent);

line 48 in AplotDialogHandler

dlg.open();

Answer 1

java.lang.IllegalArgumentException: Argument not valid

…

at org.eclipse.swt.widgets.Label.setImage(Label.java:337)

JavaDoc of Label tells you the following:

IllegalArgumentException –

ERROR_INVALID_ARGUMENT – if the image has been disposed

So, it seems like you already disposed the image you are trying to set.

---

There are two solutions for this:

1. Wait with the disposal of the image until your main application is closed.
2. Dispose the image when the dialog is closed, but create a new one, when you reopen it.