[PATCH] further simplify UploadDialog

[marcello@…]

This patch simplifies UploadDialog in a further attempt to nail #20690.

• The dialog was simplified by combining the function of two radiobuttons and one combobox into one combobox.
• When an open changeset was selected on tab 2, existing tags on the open changeset could overwrite the data the user entered on tab 1. The user might spot this by looking closely at the tag table on tab 2, but then he may not. This non-obvious behaviour was removed.
• The exception thrown when closing an already closed changeset was fixed.
• More cosmetic changes to the dialog.

Maybe also fixes #19319, #21387 (added revalidate()).

[Don-vip]

In 18283/josm:

fix #21427 - further simplify UploadDialog (patch by marcello, modified)

• The dialog was simplified by combining the function of two radiobuttons and one combobox into one combobox.
• When an open changeset was selected on tab 2, existing tags on the open changeset could overwrite the data the user entered on tab 1. The user might spot this by looking closely at the tag table on tab 2, but then he may not. This non-obvious behaviour was removed.
• The exception thrown when closing an already closed changeset was fixed.
• More cosmetic changes to the dialog.
• Maybe also a solution to #19319, #21387 (added revalidate()).

[Don-vip]

Thank you!

[gaben]

Something is still not right with the upload dialog. Now I ran into an issue when an open changeset doesn't show up at all but a closed one does.

Edit: It never worked correctly, but at least reopening the upload dialog / clicking the refresh button fixed the issue, until now.