You want to create a Gradient Feather effect. Look in InDesign Help for Gradient Feather. The settings are in the Effects panel. You can change the direction with the Gradient Feather tool.
If you're still having problems, post a screen shot using the camera tool in the posting editor.
Thanks Steve. That's the effect I was using, but it doesn't work for me, so I'm either missing a step or doing something wrong, I would guess.
I'll start from scratch and give it another try, and this time log each step and setting I do, and post that - maybe you or someone else can spot where I've gone astray. But it's nearly 3 a.m. here now, so it'll have to wait for tomorrow now. Thanks for replying, though. :-)
OK, did two things to fix it.
Firstly, I realised that I'd already applied a partial transparency of 84% to the panel before I had decided to try a gradient. So I reset it to 100% fill, and tried again. This time the feather gave me a transparency, but not a gradated one. Hmm.
So I trashed my preferences and rebuilt them, and now ... all is well !! I'm getting the result I'd hoped for. Big smiles !
So. I don't understand how preferences can get corrupted -- ID hasn't, to my knowledge, crashed or hung since I first did a clean install of this version, for instance -- but at least I know how to fix it.
Peter, Steve, thanks for your help.