Nullpointer Exception occurs, when applying a template to an existing entry and switching to "Entry" tab - see screenshot
You seem to have CSS turned off.
Please don't fill out this field.
You will have to provide more details, I cannot reproduce this. It must be related to the template or the new entry so If you could provide exact minimal steps like:
Create a new keepass file, create a template folder named X, create an entry in that template folder and add a custom 5 line edit field, set as a template. Create an entry in the root keepass folder, set its parent to the template created and then immediately switch to the entry window.
I believe this was the listbox bug that is fixed in the next version.