title: Strange behaviour of code minings at line ends
body: <p>I have started implementing code minings in our plugin. As we try to support older versions of eclipse as well, the initial development platform was 4.19. As this release only provides <code>LineHeaderCodeMining</code> and <code>LineContentCodeMining</code>, I have created my own <code>LineEndCodeMining</code> that places the mining at the end of a given line. It is done by calculating the offset of the last character in the line and placing a <code>LineContentCodeMining</code> there. The feature based on this is quite similar to Gitlens; I display git commit info at the end of the current editor line.</p>
  <p>Our text editor code overrides <code>handleCursorPositionChanged()</code> and that method is responsible for adding/removing these line end minings if the cursor moves to another line. At the end of the handler</p>
  <pre><code>((ISourceViewerExtension5)getSourceViewer()).updateCodeMinings();
  </code></pre>
  <p>is called to update the minings.</p>
  <p>This works well in eclipse 4.19, however updating the minings works weird on recent eclipse versions: many times these line end minings are displayed only if I move the cursor again (even if I move the cursor horizontally, and this case the code mining related code paths like <code>updateCodeMinings()</code> are not called at all).
  Just for testing, I have modified my code to place the minings at the character before the last one and that works perfectly. It seems the problem only occurs with content minings placed at the last character of a line.
  I have the feeling it is somehow related to introducing <code>LineEndCodeMining</code> in Eclipse 4.23, but it is just a guess.</p>
  <p>I would be happy for any pointers.</p>
  <p>Extra question: as a workaround I was thinking of using <code>LineEndCodeMining</code> if it is available (eclipse &gt;= 4.23) and use my own code for older versions. I am wondering what is the correct way to check for the availability of <code>LineEndCodeMining</code>; I cannot find any eclipse style IxxxxxExtension interface for this; should I check the Eclipse version itself?</p>