It’s a long time since I use the stock firmware but on the community edition there is an XPos control which moves the display horizontally.
There are 4 program slots available for use by application firmware. Normally the a main scope application takes up 2 of these (the first 2). Other applications are compiled to go into different slots and you access these by holding down one of the main buttons when starting up.
Although it would be possible to have both stock and an alternate main scope installed (e.g. stock in 1+2, alternate in 3+4) most of the main scope applications are compiled for 1+2.
Loading new firmware is really quick and easy so it is very simple to try an alternate scope program and then revert back, but having tried say the community edition you won’t switch back anyway.
If you turn on the device with the left (run) button held down then the device enters load mode and when you connect to a PC it shows a simple disk drive. Most of the time you just copy a hex dump of the new firmware into the drive and it uses that to write the new firmware into the slot(s) addressed by the hex. For updating binary data like the FPGA code then you need to put in an .adr file first followed by the binary. There are lots of guides available see for example