Transient and sporadic issue in rendering

[hallba]

On analysis the canvas elements are inappropriately resized, as seen in this screenshot

Nothing obviously wrong in console:

[ResultsWindow] content option changed, updating reference only
tool.js:21088 [ResultsWindow] Comparing content - old: undefined new: <div class=​"scrollable-results">​…​</div>​ same?: false
tool.js:21091 [ResultsWindow] detaching old content, appending new
tool.js:21086 [ResultsWindow] content option changed, updating reference only
tool.js:21088 [ResultsWindow] Comparing content - old: undefined new: <div class=​"scrollable-results">​…​</div>​ same?: false
tool.js:21091 [ResultsWindow] detaching old content, appending new
tool.js:21086 [ResultsWindow] content option changed, updating reference only
tool.js:21088 [ResultsWindow] Comparing content - old: undefined new: <div style=​"height:​ 100%;​">​…​</div>​ same?: false
tool.js:21091 [ResultsWindow] detaching old content, appending new