memory leak when annotating PDFs

When annotating PDFs or scrolling through larger PDFs that contain lots of annotations, evince claims a large amount of memory and never releases it. This becomes especially apparent when using the highlight feature, i.e. highlighting various parts of the text on the PDF.

On a 12-page PDF, not annotated, evince used about 35 MB of RAM and claimed an additional 30 as soon as I used the highlight feature the first time, then this repeats with about the same amount or more for each additional highlight. The interface starts to lag visibly the more memory is allocated.

Occasionally, the memory usage goes down by a few percent when scrolling, but it tends to allocate more and more memory until the system runs out of memory.

Using the same 12-page PDF with about 100 highlighted lines and quickly scrolling through the document multiple times, evince reached about 6 GB of memory usage in less than one minute.

This issue also makes closing documents very slow, taking about 5 to 10 seconds for each gigabyte of memory allocated.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: evince 3.34.1-1build1
ProcVersionSignature: Ubuntu 5.4.0-12.15-generic 5.4.8
Uname: Linux 5.4.0-12-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu16
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Feb 9 23:13:02 2020
InstallationDate: Installed on 2020-01-30 (10 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200124)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/zsh
SourcePackage: evince
UpgradeStatus: No upgrade log present (probably fresh install)