[Modal] Animation of modal entering not working in some conditions

[nonjene]

Issue summary

When open a modal in some conditions (reproduction), the fade up animation effect is seems be interrupted.

After debugging, it seems the transition of stage .Polaris-Modal-Dialog--entering is not needed, then add transition: none to this css selector, the problem fixed.

here is the sandbox reproduction: https://codesandbox.io/s/m7n0q878k8

Expected behavior

Always show the modal's entering animation.

Actual behavior

Not always show the modal's entering animation.

Steps to reproduce the problem

1. go to the reproduction example
2. click the persist actions in the resource list
3. click open modal
4. the modal showed without animation

Hack the problem:

1. click the Add the fix of modal transition button
2. click again of the persist actions's open modal
3. the animation work

Reduced test case

https://codesandbox.io/s/m7n0q878k8

Specifications

• Are you using the React components? (Y/N): Y
• Polaris version number: 3.12.0, 3.xx
• Browser: chrome version 74
• Device: macbook
• Operating System: macos

This issue has been inactive for 180 days and labeled with Icebox. It will be closed in 7 days if there is no further activity.

[chloerice]

Hey @nonjene, I believe this was fixed by #2076. Please reopen if you are still able to reproduce with v4.2.0 or higher.