Qtype gapselect: currency like options ($4) do not show in the selector

Create a 'Select missing words' (gapselect) question and add an option group with values that are currency like e.g. '$2 or $4.99'. Preview the question and see how the select dropdown has '' where the option should show the currency value.

Note that it is possible to 'sort of fix this' by putting a space between the $ and the first digit.