Hi @dpstear 

You can create an integer variable on your form and use the count function to count all the checked items in your multiple select control:

you can then have a rule like this:

or like this:

The rule makes sense to me but I cannot get the variable to work. I am using SharePoint online so my formula builder does not look like that. Any suggestions how to create that formula that way? 

Thanks for all your help!

Donna

The solution from @Prineel_V3 should work if you are using the New Responsive designer.

What forms designer are you using in O365 -- New Responsive, Responsive, or Classic?

Responsive designer. Sorry I forgot to add that.

Thanks for clarifying. Below is how is accomplish this in the Responsive designer.

1.  Create a form variable by clicking on the Form Variables button in the ribbon.

• Name = intCount
• Formula = count(Color Select)   “Color Select” is the Choice control name

2. Create a rule on the control(s) that need to be hidden.

• Rule name = Hide Controls
• When = lessThan(_intCount, 2)
• Then = Hide

3. This should hide the control(s) when zero or one choices are selected.

That works perfectly! Thank you so much for your help.