The second notebook's page, dubbed MIXAL, shows you the MIXAL source of
the currently loaded MIX file.
The information is presented in two columns. The first column shows the address and memory contents of the compiled MIX instruction, while the second one displays its corresponding MIXAL representation, together with the source file line number. The current location of the location counter is highlighted in grey, while any set breakpoint is marked in red. You can set/unset breakpoints by clicking on any line in this view which has an associated memory address.
The colors used to mark the location pointer line and the breakpoints
can be customized with the Settings->Colors... menu command. When you
click on this menu item, a dialog showing the current line colors will
appear.
The following figure shows the change color dialog.
Clicking on any of the colors will produce a color selection dialog for choosing a new color for the given element. In this way, you can change the foreground and background colors used for drawing the current line, the lines where breakpoints have been set and plain MIXAL code lines.
You can change the font used to display the MIXAL source code using the Settings->Change font->MIXAL menu command.