Unable to reach buttons in withdraw popup on mobile

[lion-200]

Describe the bug
When I click on Withdraw button in my Wallet page, I cannot reach the "Withdraw" button on the bottom right of the popup window. Also if I try to scroll, nothing happens. Seems like it's scrolling the page behind the popup instead of the popup itself.

To Reproduce
Steps to reproduce the behavior:

1. Go to Wallet
2. Click on Withdraw
3. Select "STEEM" as token to withdraw
4. Try to reach the "Withdraw" button on bottom right

Expected behavior
Make it possible to scroll in popup.

Screenshots

Smartphone (please complete the following information):

• Device: iPhone 8
• OS: iOS 13.3
• Browser Safari