Opening a NbDialog freezes layout components graphically

### Issue type

**I'm submitting a ...**

* [x] bug report
* [ ] feature request

### Issue description

**Current behavior:**
Using a NbDialog Component in connection with dynamically enhancing elements like lists or other endeavors that modify the page (page as being the outlet in one-column-layout) of height (even switching components) causes theming issues. Those basically freeze the location of the footer and sidebar colors although the page's content enhances in the meantime.

**Expected behavior:**
Not having described graphical glitches (as seen e.g. in the screenshot below).

**Steps to reproduce:**
A great reproduction would be one of the examples on the nebular doc:

### Other information:
Versions include those of your sample doc server. Angular 9 (Ivy disabled) and Nebular 5.0.0 has been used personally.