RFR: 8306119: Many components respond to a mouse event by requesting focus without supplying the MOUSE_EVENT cause [v2]

[Prasanta Sadhukhan]

> Many Swing components request a focus transfer in response to a mouse event, but fail to supply a Cause when requesting focus. A focus event listener will find the cause to be UNKNOWN, but MOUSE_EVENT would be more appropriate. 
> Fixed by adding MOUSE_EVENT cause to requestFocus() when it is called for mouse events...
> 
> All jtreg/jck tests are ok..

Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:

  Add test

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14004/files
  - new: https://git.openjdk.org/jdk/pull/14004/files/2c11ea27..1118436f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14004&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14004&range=00-01

  Stats: 103 lines in 1 file changed: 103 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14004.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14004/head:pull/14004

PR: https://git.openjdk.org/jdk/pull/14004