Bug 63223 Use null to clear message text instead of empty string
I200405200800 StatusLine in jface uses setMessage("") to clear the text while the documentation says you should uset setMessage(null) to clear the text. The code path is slightly different for "" versus null, but using null makes the intent of the caller clearer.
bundles/org.eclipse.jface/src/org/eclipse/jface/action/StatusLine.java
}
        };
        if (fProgressBar == null)
            return;
        fProgressBar.getDisplay().timerExec(DELAY_PROGRESS, timer);
        if (!animated) {
            fProgressBar.beginTask(totalWork);
        }
        if (name == null)
            fTaskName = "";
        else
            fTaskName = name;
        setMessage(fTaskName);
    }
    /**
     * Notifies that the work is done; that is, either the main task is completed or the
     * user cancelled it.
     * Done() can be called more than once; an implementation should be prepared to handle
     * this case.
     */
    public void done() {
        fStartTime = 0;
        if (fProgressBar != null) {
            fProgressBar.sendRemainingWork();
            fProgressBar.done();
        }
        setMessage("");
        hideProgress();
    }
    /**