Enhance the behaviour of textboxes

[SH-Tang]

Currently, the text boxes only commit their values when the user moves the focus away from the textbox (by for example clicking on a different control component). The user should be able to commit the value with a return key without losing focus of the component.

[SH-Tang]

In addendum, also noticed that swapping from tabs, without commiting the values (by losing focus), the value is not committed.

Potential fix: https://stackoverflow.com/questions/10208861/wpf-data-bound-tabcontrol-doesnt-commit-changes-when-new-tab-is-selected

For the enter key (or other key), might be interesting to take a look at: https://stackoverflow.com/questions/563195/bind-textbox-on-enter-key-press

[SH-Tang]

Implemented per rev ad0816823b49de5743e191d558e21bd85c44f2e3 and ready for merge back

[SH-Tang]

Merge back performed per rev 72f48fa745e408f35a5da09bf5c2a292a91a2391