1.9.4.1048 no grayscale representation when clicking on spare channels

[altae]

Normally clicking on a selection which was saved as a spare channel shows a grayscale representation of the selection. This functionality does not work anymore in the latest beta.

[Patrick Connor]

Thank you @altae

This has already been acknowledged in the recent 1.9.4 Mac beta, so is likely to be fixed at the same time.