Thumbnail click point of reference breaks after zoom.

[menocsk27]

Bug report

Expected behaviour

Click should be related to the center or a corner of the thumbnail view box.

Actual behaviour

Click loses reference to the thumbnail view box

Steps to reproduce the behaviour

1. Open the thumbnail demo https://bumbu.me/svg-pan-zoom/demo/thumbnailViewer.html
2. Click somewhere on the thumbnail, the view box will snap its center to the mouse position (kinda, it already breaks towards the upper left corner)
3. Zoom in for more clarity, example:
   
4. Clicking anywhere on the thumbnail shows that the mouse is not aligned to the view box anymore, it snaps to other places.

Gif version of these steps:

Configuration

• svg-pan-zoom version: demo
• Browser(s): chrome
• Operating system(s): win10
• A relevant example URL: https://bumbu.me/svg-pan-zoom/demo/thumbnailViewer.html

[Minniball]

I need the feature as well, can someone solve the issue?