When opening the simple explorer tool through the tool manager :

Ametys.tool.ToolsManager.openTool('uitool-simple-resources-explorer', {});

If the tool is already opened, the explorer tree is systematically reloaded and the resource root node is selected.
This looks like a regression because in the previous version if the tool was already opened, the current selection was preserved (and perhaps the current selected node was reloaded but I am not sure).

This is important to preserve interaction mechanism with some other tools (the rights assignment tool on the /resources context in my case).