Problem creating listbox with no item selected

[GOGGS]

When creating a dialog box containing a listbox with the execDialog function I am having a problem with Adobe Acrobat Reader DC. I want to create a listbox with no item selected. When using the array like { "Line1": -1, "Line2": -2, "Line3": -3} the "Line1" item is selected when it has a code beside it of -1 not +1.

There is no problem when using an alterantive to Adobe Reader I have.

Thanks for any help.

[Thom Parker · Accepted solution]

Definately a bug in the ADM.  I do not believe there is a way to get around this for a single selection list. 

Would adding a blank entry as the default selection help?  

[GOGGS · Accepted solution]

Thanks for confirming this is a bug. I have the choice of adding a blank entry or an OK button to get aroung the problem. It had been set up to run a function on clicking the relevant line.