Forge Viewer PDF extension allow Document Browser to stay docked to side

Solution 1:

It seems that most of the properties and functions of the Autodesk.DocumentBrowser extension just make it easier to get to the various DOM objects of the panel, but then you can use their DOM functions and properties to achieve what you need. Here is the source code of the extension: https://developer.api.autodesk.com/modelderivative/v2/viewers/7.*/extensions/DocumentBrowser/DocumentBrowser.js

To move the panel to the top-left and show the Thumbnails tab you can do this:

let ext = await NOP_VIEWER.loadExtension("Autodesk.DocumentBrowser");
ext.ui.panel.container.style.left = 0;
ext.ui.panel.container.style.top = 0;
ext.ui.panel.panelTabs[1].click();