Describe the bug:

Seeing some lag in the form of a black line on the right side when resizing horizontally. Seeing flash of black between items in the window on resize.

To Reproduce:

Steps to reproduce the behaviour:

1. cd ~/go/src/github.com/fyne-io/fyne/cmd/fyne_demo
2. go run main.go
3. Drag side of window in and out quickly to resize.

Screenshots:

Lag

Black flash

Device:

• OS: Ubuntu
• Version: 18.04.4 LTS
• Graphics: Nvidia Quadro P1000/PCIe/SSE2 with nvidia-driver-440
• Go version: go1.14.2 linux/amd64
• Fyne version: v1.3.0