.NET 4.8.1
C1.WPF.FlexViewer 4.6.20251.877

memory leak

Hello,
I'm experiencing a serious memory leak with the C1FlexViewer.
The C1FlexViewer instance remains in Memory and is not being released properly.
To reproduce the issue, I created a sample project with the folloewing scenarios:

WPF Window -> C1FlexViewer
WPF Window -> Microsoft DocumentViewer

WPF Window ->ElementHost-> C1FlexViewer
WPF Window ->ElementHost-> Microsoft DocumentViewer

In both scenarios using C1FlexViewer, a significant memory leak remains (several megabytes).
According to heap analysis, the C1FlexViewer instance is never garbage collected.

In our application, we use C1FlexViewer together with and ElementHost. 
I used Microsoft DocumentViewer as a reference for expected behavior. 
Even when hosted inside an ElementHost, the Microsoft DocumentViewer is released correctly and does not leave a significant memory leak.
The same is true for the scenario without an ElementHost

Could you please help me understand how to resolve this issue?
Is there a known workaround or recommended cleanup procesdure?

Best regards from Germany!