Specifically with Swing JTextComponents, sometimes after primary clipboard text transfer (with middle-mouse button), the clipboard contents are not always cleared or updated.

To reproduce this bug, a sample application is attached, "ClipboardStringTestSwing.java".

With this bug, after a text selection was made and then deselected, the contents of the primary clipboard should be cleared (updated by the deselection) - the end result is that if there's no text selected and middle mouse button clicked, you will unexpectedly get data transfered to your TextComponent.

Steps to reproduce:
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If there is no text selected, clicking the middle-mouse button will transfer whatever was last in the primary clipboard.

1) Click left mouse-button in TextField1 to go into insert mode.
2) Select text "Hello" in TextField1,
3) Click the middle-mouse-button in TextField2 and the text should transfer as expected.
4) Click left mouse-button in textField1 to deselect your previous selection (nothing should be selected at this point).
5) Click middle-mouse-button in TextField2. The text "Hello" will be transfered instead of null.

- This bug is not reproducable with AWT TextComponents.
- Tested this with Solaris 2.7 and 1.4.0-beta_refresh-b70.