We have the fix available in the latest release. Please update Illustrator using Adobe Creative Cloud application to the latest build for version Illustrator CC 23.0.
Please refer to our knowledge base FAQ – https://illustrator.uservoice.com/knowledgebase/articles/1844590 if you face difficulty in update.
Or get in touch with us at any of the other support channels – https://helpx.adobe.com/support.html
Ashutosh Chaturvedi | Sr. Quality Engineering Manager – Illustrator
Adobe. Make It an Experience.Karan Parkin commented
Illustrator has a nice way to size the interface... what about InDesign? There is no slidebar, like the one in Illustrator?