Drag&drop images does not work properly in Firefox browser

Repeat steps:

  1. Open Folder with images (I've tried on Linux)
  2. Open the post editor in the Denser
  3. Drag and drop image to the post editor in the Denser
  4. Image is not moved to the post editor

but another way to drag&drop is working properly

  1. Open the post editor in the Denser app
  2. Click Select image button than files editor will be opened
  3. Drag and drop image to the post editor - this way works