Color Editor Factory Example - Columns can be moved even when cursor is out of the window

Description:

Columns can be moved even when the cursor is out of the window's frame.
Steps to reproduce:

1. Open the Color Editor Factory Example
2. Drag the columns out of the window frame

Expected behavior:

It should not be possible to drag the columns out of the window frame. The dragging should be confined to the window frame.
Observed behavior:

It is possible to drag the column out of the window's frame.
Special notes: