Can't set breakpoints in Eclipse
When you double click the gray bar a blue ball appears? If it appears, try to hover you mouse over it and It may say "Line Breakpoint:Blablabla"
Otherwise, try to check if you are using a java editor to open your file. To check this right click the file you want to open, go to the Open With entry and check if Java Editor is selected, if there is not such option this means that you have not the JDT installed and is probably better to download the Java version of eclipse from its official website.
If none of the previous options helped, its probably a bug and you should report it to the eclipse bug system if you would be so kind.
- Right click on file(i.e. example.js)
- go to Open With
- click on Other
- click on Internal Editors radio button
- Select Java Editor from list
Now you can set the break point by right click and selecting one from available methods i.e. toggle breakpoint / line/method etc.