Eclipse has a context menu item to hide the entire toolbar of RCP.
Where is the corresponding menu item to show the hidden toolbar?
I know it should be shown if using a new workspace. However I hope find the related feature in the GUI of eclipse.
Use the Window menu, you have a "Show toolbar" option there.
I'm on Mac OS X, and one thing I always forget about is the stupid lozenge button in the upper right corner of the window. I hit this by accident and was going nuts trying to figure out where my toolbar had gone until I (experimentally) hit it again.
I tried one solution here and worked for me. If you can not reset or change something from eclipse GUI, Go to your project folder eg. "Workspace". Delete folder ".metadata". Now open eclipse again and browse "Workspace". Import your projects from the "Workspace". It will reset eclipse to default.
In eclipse oxygen version it is available under Windows --> Appearance --> Show Toolbar
来源：https://stackoverflow.com/questions/4301637/how-to-show-the-hidden-toolbar-of-eclipse