Fix tab order in the main window

[PEERSOFTdev]

Bug description

What I found on Windows is that when navigating by a Tab key in the main window, the order in which controls are being encountered by a Screen Reader makes the interface confusing as to which controls belong to source and translation.

Steps to reproduce

1. Open the main window.
2. Repeatedly press TAB to go through various buttons and other controls in the main window. You will encounter a checkbox representing the language being translated, or "Auto" just before the source edit area (by before I mean that if you press TAB once again you will end up in the source edit field and the described checkbox was the previous control in the Tab Order).
3. When you TAB further, you will go through the translation edit field and other action buttons. Then, you will encounter another checkbox for translation language, or "Auto" again. The problem here is that you cannot easily tell whether this checkbox belongs to the source or translation field.

Expected behavior
I would propose either:

1. To make the Tab Order so that both checkboxes are one next to another, the source language one being the first. These checkboxes could precede both edit fields, so that in the end you would tab through the source language checkbox, translation language checkbox, source text edit field and finally the translation edit field.
2. Place every language check box before or after the appropriate edit field so that you would automatically associate the edit field with the selected language. In the end, the Tab Order could then look like "source language", "source text", "translation language", "translation text".

Environment

• OS: Windows
• Crow Translate version: 2.11.1

Additional context
My Screen Reader is NVDA, however, the same behaviour can be reproduced with Narrator.