title: Eclipse generates "source not found" in v. 2020-03
body: <p>Scenario: Debugging a JavaFX library project that is based on the standard Maven model. For my IDE I'm using Eclipse v. 2020-03, operating system is Windows 10.</p>
  
  <p>A break point is set on a class that is opened in a tab in the Debug perspective. When the break point is hit a <em>new</em> tab is displayed for the <em>same</em> class together with (i) a message 'source not found' and (ii) a button labeled 'Edit source lookup path...' that, when pressed, displays a dialog with various options. When the 'Save' button is clicked on the dialog (doesn't matter if any option is selected) the source code appears for a split code in the <em>new</em> tab before disappearing in favor of the aforementioned message and button.</p>
  
  <p>This problem manifested itself when I upgraded to Eclipse v. 2020-03 from v. 2019-12. It is worth noting that this was <em>never</em> a problem in v. 2019-12, and that it was <em>never</em> necessary to make any tweaks or special adjustments via the traditional 'Windows/Preferences/[... take your pick]' solution. In other words, this was <em>automatically</em> handled properly without special intervention ... as it should be.</p>
  
  <p>In an effort to get a working IDE I went back to using the 2019-12 version, and everything worked well ... until I received a message that updates were available for some of the modules. So I applied the updates and reloaded Eclipse, and lo and behold, the very problem that I was trying to avoid by returning to the old installation was injected into that version of Eclipse so that it doesn't work either.</p>
  
  <p>I am aware that this question has been asked in innumerable incarnations over a number of years. Indeed, there are as many different solutions as the number of times the question has been asked. However, there should be an already-built-in-approach-that-prevents-the-problem-in-the-first-place, and that is not the case.</p>
  
  <p>A bug report has been submitted to Eclipse Bugzilla (#561476); at the time of this writing there has been no response or acknowledgement.</p>
  
  <p>If anybody else has encountered the same issues and found an effective way to deal with them I would be grateful for some guidance. Thank you.</p>