Layer Mask box has disappeared

[sheldrake]

The layer mask box (the blank square to the right of the slider/graph thingy) on the adjustment layer has disappeared. What have I done?

[kevq]

Which adjustment layer are you trying to use.
Normally the Adjustment Box opens in its own window, not on the layer. If you have opened an adjustment layer and wish to open the controls you double click on the left hand thumbnail in the the layers palette.
Hope this helps.
Kev.

[sheldrake]

Many thanks for the quick respose. I'm adding a Levels Adjustment layer and asking it to "Group with Previous Layer". It does open in its own window, but it only has one box with a graph/slider icon and is indented with a down arrow to its left. There's not a link symbol and a second blank white box to its right as there's been any other time I've done this. Seems to be the same problem with all the other types of adjustment layers. I have a feeling that I may have inadvertently changed a setting, or maybe I'm just doing something dumb...