Cannot initiate "Fit Yby X" from new data table

[#1]

I'm a casual user of JMP (far from an expert), and newly upgraded to JMP 17. If I create a new data table and enter in the first two columns, I cannot then complete a "Fit Y by X" analysis. The dialog window opens, but I am unable to highlight and drag either column into the "X" or "Y" fields. Some other notes or observations on the process include:

1. The data is continuous numerical, with column names
2. I am able to analyze the data using the "Fit Model" and "Graph Builder" options
3. I have tried both entering the data manually and importing it from excel with the same results
4. I can open an old JMP file with similar data, and "Fit Y by X" works as it should
5. If I use the Columns option to pre-select column roles, "Fit Y by X" works as expected.

I suspect I am missing some critical step, but am mystified. Thanks in advance for any and all suggestions.

[#2]

Welcome to the community.  If you wouldn't mind attaching your data table, we'll have a look.