Please make it more keyboard friendly

First off, great work on making a very neat plugin. The only problem I see in using it as my everyday POS system is that it needs mouse movement for many of the things. I do not have enough hands to hold the barcode scanner, the products, operate keyboard, and also operate mouse. Not to mention that mouse significantly slows down the billing speed.

My suggestion is to make it more keyboard friendly and minimize the need of mouse in the following ways:

• Remove unnecessary tab stops. Right now, clicking on Tab cycles through even the non-editable elements, e.g. product name in the cart.
• Optimize tab sequences for the most used operations. For example, when I open the number pad UI to change quantity/price, I would most likely want to type a number on keyboard and hit Enter. So the existing quantity/price should be in focus and selected, and next tab stop should be the green Enter button. As of now that button is about 15 tabs away.
• Use other keys apart from Tab. For example, we can use arrow keys to navigate to products/categories instead of using repeated Tab keys, or we can use the Enter key for ‘submit’ button selection (like the green checkmark key in price/quantity number pad).
• Create keyboard shortcuts for most used operations, e.g. toggling between text/barcode search.

These changes will significantly improve the usability.