Update info panel when switching classes

[IotaBread]

When you change the current tab to another (already open one), the info/identifier panel isn't updated, so changing its name actually changes one in the tab you came from. The panel should be updated to reflect the cursor position in the open tab

[ix0rai]

I've been screaming about this in my head for ages but for some reason never realised we could fix it. high priority :p