Only activate your plugin and Gravity form together on any theme.
The toggle on the dropdown for the selection of merge tags is not triggered. when the toggle is active, the article tag is added the gform-dropdown–open class when opened and the aria-expanded attribute of the button goes from false to true.
Regarding the sidebar which allows you to select and manage field parameters, your styles are added to the buttons. There is a double arrow and the hover completely hides the text which has changed to white whereas it is normally black on a gray background.
Do you need a temporary test environment with GF enabled where you can configure your plugin?