Problem with update Melting temperature in Silico PCR workflow

Reproducible in debug version 47.dev. In 46.0 all works fine.
Scenario:

1. Open In Silico PCR element in Workflow Designer
2. Melting temperature by default is Primer3 in Option Panel instead of Rough like in 46.0
3. Open Melting temperature dialog, select Rough algorithm, push OK
4. Dialog is closed, but  Primer3 is still displayed, field is selected
5. Click on Melting temperature label
6. "Rough-tm-algorithm" is displayed on the screen. It's correct.
7. Again click on "Rough-tm-algorithm"
   Unexpectedly "Primer3" is displayed, see attachment.