Bug 58777 [Viewers] add API to not deactivate CellEditor on FocusLost
TableViewerImpl installs a FocusListener on CellEditors, which calls applyEditorValue() on focusLost events. This FocusListener must be removed since applying the editor value is not always the wanted behavior on focusLost. Subclasses of CellEditor already handle focus loss in an extensible way: they install their own FocusListener and call a hook method focusLost() (which can be extended or reimplemented by subclasses with special needs). To support content assist in table cells (such as in the Change Method Signature dialog), we need to stay in editing mode even while the proposal list has focus. This is currently not implementable, since TableViewerImpl deactivates the CellEditor even if the CellEditor's focusLost() is reimplemented. The fix is to simply remove the redundant FocusListener in TableViewerImpl.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CellEditor.java
SafeRunnable.run(new SafeRunnable() {
                public void run() {
                    l.propertyChange(new PropertyChangeEvent(this, actionId,
                            null, null));
                }
            });
        }
    }
    /**
     * Sets the style bits for this cell editor.
     * 
     * @param style the SWT style bits for this cell editor
     * @since 2.1
     */
    public void setStyle(int style) {
        this.style = style;
    }
    /**
     * Returns the style bits for this cell editor.
     *
     * @return the style for this cell editor
     * @since 2.1
     */
    public int getStyle() {
        return style;
    }
    /**
     * Returns the control used to implement this cell editor.
     *
     * @return the control, or <code>null</code> if this cell editor has no control