Block Pallete and Views are Dissappear

First, this project function normally..
And then i tried to see another project, (clicked My Project)
And then this was happened to me, i tried all of my project and they were all the same
The Blocks on the left didn't appear also in viewer side

I've tried to click the white side (click left and click right) but it wouldn't show anything
What should i do? 

Thanks in Advance

My first guess is that you need to update the browser.  What version of Chrome do you have?  You need the newest of either Chrome or Firefox.