Last row of monomers in Sugars, Bases, and Phosphates sections is not visible in popup Ketcher

[Zhirnoff]

Description:
When using the popup version of Ketcher, the last row of monomers in the Sugars, Bases, and Phosphates sections of the RNA Builder library is not visible to the user. The scrollbar appears to reach the end of the list, but the final monomers are cut off and cannot be accessed via scrolling.

Steps to Reproduce

1. Open Ketcher in popup mode.
2. Switch to RNA Tab.
3. Open the Sugars, Bases, or Phosphates section.
4. Scroll to the bottom of the list.

Actual behavior
The last row of monomers is hidden and cannot be accessed due to scroll limitations.
Additional Info:
This issue seems to occur only in the popup version of Ketcher. In the full-page version, the list displays correctly.

Expected behavior
The entire list of monomers should be visible or scrollable, including the last row.

Video

2025-04-03_16h58_13.mp4

Desktop:

• OS: Windows 11
• Browser Chrome
• Version 133.0.6943.127 (Official Build) (64-bit)

Ketcher version
[Version 3.3.0-rc.1]
Indigo version
[Version 1.31.0-rc.1]
This bug was found while testing: #6519