undo fills in stuff which never was existing there - in the changeset comment

[aseerel4c26]

0. have previous uploads (so you have a upload comment history)
1. set upload.comment.max-age = 0 (more info: see #9438), so the comment field is empty by default
2. edit some data
3. press the upload button (upload window appears)
4. hit ctrl+z.

Expected: nothing, since I did not enter text in this field before, so there should be nothing to "undo".

Actual: the last changeset comment appears.

Note: this also happens if you enter any text and then Ctrl+Z and hold the keys, because you want to undo everything you've entered. Expected is that you get an empty field. Actual is that you land in some old comment.

In JOSM v. 8103 (although I guess that never was different). System: Linux, Java version: 1.8

[Don-vip]

In 14977/josm:

ensures consistency of upload comment:

• fix #11168 - ctrl-z/undo could reset unwanted old changeset comment
• fix #13474 - selecting "new changeset" after having entered a changeset comment did reset it to the previous value
• fix #17452 - ctrl-enter while typing a changeset comment did upload with the previous value
• fix behaviour of upload.comment.max-age: values were reset after 5 months instead of intended 4 hours because seconds were compared to milliseconds
• avoid creation of unneeded undo/redo internal classes for non-editable text fields
• ensures consistency of upload dialog if upload.comment properties are modified manually from advanced preferences
• add a source attribute to preference events to know which class modified the preference entry
• refactor reflection utils

[aseerel4c26]

Thank you! Test case above works now. Tested with version 14986 openjdk 11.0.3. :-)