Flow rate touch screen menu only shows and adjusts the flow rate for T0, even if T1 is active.

[cdsmith69]

On the TAZ Pro and TAZ 8, the touch screen flow rate menu only shows and adjusts the flow rate for the T0 extruder, even if T1 is active at the time. So there is no way, from the touch screen, to set the flow rate for the second extruder.

Before we fix this, we need to decide how it should work.

• Do we just set the flow rate for both extruders? This is probably what most users would expect to happen, but it doesn't give the option to set them to different values.
• Do we set the flow rate for the active extruder? If we do this and someone wants to set the flow rate for both extruders then they would have to stand at the printer and wait for the second extruder to become active. And there may be issues with the menu not working properly unless you back out and go back in or make it update with the extruder switch.
• Do we add a switch to the menu that says "Set rate for both extruders?" with a yes/no switch?