FIX: Fixed TypeError when setting design mode #964

Job	Run time
Code style	47s
Documentation Style Check	13s
Tests and coverage (windows-latest, 3.8)	56s
Package library	13s
Tests and coverage (windows-latest, 3.9)	1m 2s
Tests and coverage (windows-latest, 3.10)	1m 1s
Tests and coverage (ubuntu-latest, 3.8)	26s
Tests and coverage (ubuntu-latest, 3.9)	26s
Tests and coverage (ubuntu-latest, 3.10)	23s
Doc build	3m 53s
Build and Smoke tests (windows-latest, 3.8)	53s
Build and Smoke tests (windows-latest, 3.9)	1m 37s
Build and Smoke tests (windows-latest, 3.10)	1m 37s
Build and Smoke tests (ubuntu-latest, 3.8)	23s
Build and Smoke tests (ubuntu-latest, 3.9)	21s
Build and Smoke tests (ubuntu-latest, 3.10)	27s
Release project	0s
Deploy development documentation	0s
Deploy stable documentation	0s
	14m 38s

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