Clipped entry dialog when editing new entry via entry field

Description

I have a matrix where one of the block types has an entry field. Entries of the available type in turn have a matrix of their own. When trying to create a new entry via the top-level matrix (rather than first creating the entry via the section page and then selecting it in the entry field), attempting to add a new matrix block causes the "dialog" to be clipped at the bottom of the screen and thus be inaccessible.

Tested with a viewport height of 1288px mainly, but the bug is visible in other sizes too.

Steps to reproduce

1. Create two sections, A and B, each with their own entry type, each with a Matrix field
2. Let the A matrix have an Entry block type selecting B entries
3. Let the B matrix have a block type with a few fields (I have a plaintext field, a radio button field with three options, and a Redactor field)
4. While editing an entry in A, create a matrix block and click "Add an entry" to get the dialog listing B entries
5. Click "New B entry" in the bottom left of said dialog (a new popup "dialog" opens showing B's title, its matrix field and Cancel/Save buttons)
6. Click to add a new matrix block in the B entry

The "dialog" grows in height to accomodate the new block, but it is not repositioned. Furthermore, the outermost viewport is not scrollable, so the Cancel/Save buttons (and other parts of the innermost dialog) are now inaccessible.

Additional info

• Craft version: 3.0.0-RC13
• PHP version: 7.0.27-0+deb9u1 (cli) (built: Jan 5 2018 13:51:52) ( NTS )
• Database driver & version: mysql Ver 15.1 Distrib 10.1.26-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2
• Plugins & versions: Asset Rev 6.0.0, Redactor 1.0.1