Human interface improvements

Hello,

thank you for providing this very helpful tool.

There are two issues that I would recommend to change:

1. Number input.

If I want to send a register or a coil to modbus I get a window that is white. Then I type in a number "1" and the field stays white. After the Enter key the field turns blue. I understand that this behaviour is necessary to allows multiple digits to me typed in.

But when hitting the transmit button when the fields is white the value in the white field stays white an the number is NOT taken by the application to the transmit buffer. and the number that goes out to the bus is the previous number and not the actual.

I whould recomment that when the transmit button is hit, the application should behave like the enter key has been hit and transfer the new value of the white field to the transmit buffer.

1. Error behaviour

When I want to transmit a register or a coil for debugging purposes on my microcontroller it can happen that my microcontroller is not responding properly. in this case all input fields in the tool are deleted. That is a bit annoying to input all numbers again. for the next test

I would recommend to keep the input fields in the case of an erroneous transmission.

Regards

Alexander