[Mac, wd] Wizard page is empty after calling a dialog and clicking "Back"

1. Open WD.
2. Select the Samples tab and open the "De novo assemble Illumina PE reads" sample.
   Expected: the "Illumina PE Reads De Novo Assembly Wizard" appears.
3. Click "Next".
   Expected: the "Trimmomatic settings" page appears.
4. Configure trimming steps:
   1. click the "..." button,
      the "Configure Trimmomatic Steps" dialog appears;
   2. click the "Add new step" button and select ILLUMINACLIP;
   3. click Apply.
      Expected: all widgets on the "Trimmomatic settings" page are displayed as normal, as expected.
5. Click "Next", then "Back"
   Expected: the page in the same state as in step 4.3.
   Current state: the page is empty.
   

Reproducible in other wizards with dialog calls.