Why can not select the brick?

During the process of creating graphics in the browser, a certain amount of cache will be generated. When the browser cache increases, this situation may occur when opening a solution. If this happens, clear the browser cache using the following steps:

Step 1: Press Ctrl + Shift + Delete simultaneously on the homepage to enter the browser's cache clearing interface.

Step 2: You need to clear the cache in both the Basic and Advanced sections. Change the time range to All time, check all the boxes, and click Clear.