Hi Gopal, I think it (disappearing tool icon) may have happened to me once. But not 100% sure so I keep an eye open to see if it happens (again). This was last week when the change was new to me.
Thank you for all the work and effort that the team puts into improving SketchUp for Web.
This is quite a change and it takes time to get familiar with the new tool sets opposed to the former “fly outs”.
I do have a wish or two (or three) though about the new toolbar. Would id be possible to have a double colom set of tools.
To have more tools instantly available I now have to shrink the tools ([Ctrl+scroll wheel) and either add more tools or add more “Recent Tool Slots”. And while I’m at it, it would also help tremendously if the “Separator” would be more visible, a much thicker line. See the need to shrink the toolbar and its icons above to see more tools (which makes the separaort even thinner).
Last thing for now, could there be an option to create a shortcut to bring up the “Extended Toolset”. Instead of having to click on the three dots.