Graph cleanup

Phis stay with regions, stop sinks to bottom,

1 files changed, 6 insertions, 2 deletions

diff --git a/graph/web/viewer.js b/graph/web/viewer.js
index 63ee195e..4a88245b 100644
--- a/graph/web/viewer.js
+++ b/graph/web/viewer.js
@@ -87,9 +87,13 @@ async function render(index) {
     if (generation === frameGeneration) {
       renderer.show(frame.snap, frame.layout, frame.evt);
       if (frame.pos >= 0) {
-        // Stepping focuses a button; focus the source so its selection is visible.
+        // A newline or EOF has no visible character to highlight. Show the last
+        // parsed character there, rather than losing the position indicator.
+        let pos = Math.min(frame.pos, program.value.length);
+        while (pos > 0 && (!program.value[pos] || /\s/.test(program.value[pos]))) pos--;
+        program.setSelectionRange(pos, pos + 1);
+        // Focus after selecting, so the browser brings the new position into view.
         program.focus({preventScroll: true});
-        program.setSelectionRange(frame.pos, frame.pos + 1);
       }
     }
     rendering = false;