Entering negative numbers when text editing is not possible

[Abhilash-Chandran]

In its current form the widget doesn't allow the entering negative numbers. Meaning it doesn't allow entering the - minus symbol to be entered. A proper regular expression needs to be created for the same. Some of the requirements would be.

1. The symbol - should only be allowed at the beginning of the entry.
2. It should not be allowed for fields with min value greater than -1.