[PATCH] Changset manager: Discussion tab: Problem with scrolling

[skyper]

What steps will reproduce the problem?

1. Open ​changeset #85329869 in changeset manager
2. Open Discussion tab in lower half
3. Scroll down an watch for rows with large height

What is the expected result?

All context of a row should be visible once when scrolling down

What happens instead?

Only the top part which fits in the window is displayed and the rest is skipped.

Please provide any additional information below. Attach a screenshot if possible.

It only works with the last row. Scrolling at least one complete row does not work here.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-11-26 22:24:27 +0100 (Thu, 26 Nov 2020)
Revision:17364
Build-Date:2020-11-27 02:30:53
URL:https://josm.openstreetmap.de/svn/trunk

[Solarspot]

Scrolling in a default Swing table aligns window borders with row borders. This is fine if table rows have small and constant height. But if some rows are larger than the others, scrolling becomes confusing. Very large rows are indeed partly skipped.

It would be better if this table is scrolled like a plain text area (e. g. JOSM status report)

[Solarspot]

In the attached patch the scrolling logic of this table is borrowed from javax.swing.JTextArea. That makes the scrolling smoother

[simon04]

In 17788/josm:

fix #20164 - Changeset manager: Discussion tab: Problem with scrolling of long comments (patch by Solarspot, modified)

[simon04]

I've added the license headers and replaced sun.swing.SwingUtilities2.getFontMetrics with table.getFontMetrics in the test code.