Tab does not indent while editing solution code

[aarchiba]

While editing the solution code, the keybindings for editing Python code are not in place - in particular, tab does not indent. This makes it very easy to have non-standard indentation in placeholder code, which is likely to confuse students when they begin entering code and using tab to format it. (I have already come across one example of this in the questions I am importing, and it required reformatting the placeholder code in order to be able to type in a correct solution.)

On the plus side this means that editing the solution code does not expose one to #16 .

[aarchiba]

I have encountered another mis-indented placeholder entry in an imported question. When non-standard indentation is present in the code editor, both tab and backspace behave in a surprising way - tab tries to guess what to advance to, and backspace only deletes the whole tab if it is a whole tab.

The code editing boxes in the editor also provide no indication of where four-space indents land, so this is an even easier mistake to make.