When I access Display and Monitor from System Settings with 3x 48" 4k TV's, a generally small window, the monitor representation is far too huge for the viewport used to rearrange the displays.  They need to scale with the dpi to represent a usable configuration.  I'll attach an image of what I mean, it's just a UI bug for abnormal sized displays vs. dpi, but makes reordering the displays a gigantic pain, requiring me to open the settings window to like 3500x1200 to reorder things comfortably.

Reproducible: Always

Steps to Reproduce:
1. Install multiple 4k tv (3x used in test bed)
2. Open "System Settings", navigating to "Display and Monitors"
3. Observe abnormally giant representation of monitors taking up 90% of the viewport, making it impossible to reorder displays without expanding the settings window to gigantic proportions.

Actual Results:  
It requires resizing of the window to almost a full display width of 3500 pixels + to manage moving displays comfortably vs. the display scaling itself according to the viewport and dpi.

Expected Results:  
Smaller representations of 3x monitors scaled into the viewport to reorder them comfortably within the given pixel space available.  Monitors x Quantity Wide should always equal less than the viewport, scaled to the space available, or resize itself appropriately for the user to manage this.

This is more dpi optimization needed with changing usages.  I am using 3x 48" hdtv's as my monitors now, something of a corner case, but I'd imagine this exacerbated with current generation 4k displays in 24-34" desktop displays shipping @ 4k too.