Thanks guys, this really saved my day too. I antecedently pressed on skip break points, if you did the same this will result on break point appearing with a backslash icon on them.

To bring it back to normal:

1. Switch to Debug perspective.
2. press on the breakpoints view tap -->> upper right hand corner of the screen, you also can go there by Window->show view-> breakpoints.
3. 5th icon from the left you will see break point with backslash. press on that one.

To confirm, try putting break point on any line, and it should appear normally.

This doesn't exactly answer the OPs question, but when trying to double click to add break points, I was getting messages stating "this feature is not enabled".

I had to right click on the break point bar and select "Breakpoint Types" -> "C/C++ Breakpoints" instead of "Default". Then it worked fine.

Here is what worked for me, just today, Run-> Remove All Breakpoints

there can be many many reasons:

The most common ones:

• .java and .class are out of sync
• wrong version of the runtime JVM
• debug information removed from the generated class
• classpath mismatch, for instance eclipse compiles into bin/ and your runtime picks up classes from classes/ (this assumes, you also compile from the command line)
• Bad Eclipse installation

First try cleaning the project by using the clean function

Project > clean...