Corrupt progress monitor dialog when switching to design page on Linux

[ptziegler]

The progress monitor that is shown when switching to the Design page is run in the UI thread and therefore blocks the internal refresh of the dialog. The result is as such:

We need to investigate what parts of the IRunnableWithProgress need to be run in the UI thread and what can be done in a separate thread. We also needs to make sure that we only switch to the Design page, once the runnable has completed.

windowbuilder/org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/editor/DesignPage.java

Lines 454 to 482 in d650c20

	IRunnableWithProgress runnable = new IRunnableWithProgress() {
	@Override
	public void run(final IProgressMonitor monitor) throws InvocationTargetException,
	InterruptedException {
	monitor.beginTask("Opening Design page.", 7);
	//
	try {
	DesignPageSite.setProgressMonitor(monitor);
	display.syncExec(new Runnable() {
	@Override
	public void run() {
	try {
	internal_refreshGEF(monitor);
	} catch (Throwable e) {
	ReflectionUtils.propagate(e);
	}
	}
	});
	} catch (Throwable e) {
	ReflectionUtils.propagate(e);
	} finally {
	DesignPageSite.setProgressMonitor(null);
	}
	//
	monitor.done();
	}
	};
	try {
	new ProgressMonitorDialog(DesignerPlugin.getShell()).run(false, false, runnable);

Bonus points if we can remove those dreadful IProgressMonitor methods in the DesignPageSite class.