Improve commit message / reword popup UI

[IceflowRE]

It would be a lot easier if there would be two input boxes, one for the title and one for the description. Currently you have to create this yourself with a newline in between. Same goes for the regular commit message UI.

[love-linger]

Using two textboxes instead of one is not making things easier in my opinion.

• Using an empty line to seperate subject and detail description of commit is a git rule, not SourceGit. This allows users using multi-line text for subject.
• Using a single textbox allows user to select/copy/cut part of string both in subject and description
• Using a single textbox allows user to move caret easier between subject and message
• After breaking away from SourceGit, users can maintain the same editing habits in text editors that supported by git.

[IceflowRE]

* Using an empty line to seperate subject and detail description of commit is a git rule, not `SourceGit`. This allows users using multi-line text for subject.

True, but SourceGit should make the behaviour easier. If i want the true Git experience i would just use the command line. Also the description box has to be multiline of course.

* Using a single textbox allows user to select/copy/cut part of string both in subject and description

How often do you need to copy both? In those rare cases you can just copy twice.

* Using a single textbox allows user to move caret easier between subject and message

Pressing Tab could behave the same going to the next input box.

* After breaking away from `SourceGit`, users can maintain the same editing habits in text editors that supported by git.

But SouceGit is not a text editor, it should not behave like one.
The two largest Git Frontends Gitkrkaken and Github Desktop also have two input boxes.