RFR: 8309460: JScrollBar leaves behind clutter for non-integer UI scales [v2]

[Prasanta Sadhukhan]

> Lines  are left behind when moving the scrollbar in the positive direction. but are cleaned up on mouse release. 
> Additonally, with right arrow clicks too, the lines are left behind.
> Seems like for mouseDragged and scrollByUnit, the dirty region of the scrollbar is not repainted leading to artifacts
> which is being done in this fix..

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

  Update

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/17484/files
  - new: https://git.openjdk.org/jdk/pull/17484/files/e758ae45..2999a329

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17484&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17484&range=00-01

  Stats: 7 lines in 2 files changed: 1 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/17484.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17484/head:pull/17484

PR: https://git.openjdk.org/jdk/pull/17484