In the buildTimeTrend view of Jenkins 1.502, the timeline only scrolls left now. This seems to be caused by a glitch in the Simile Timeline widget code itself, that is tickled by the second patch in JENKINS-6439, https://issues.jenkins-ci.org/secure/attachment/20289/JENKINS-6439-2.patch

Editing

var d = new Date(${it.lastBuild.timeInMillis});

to instead read:

var d = new Date(${it.lastBuild.timeInMillis}-1);

fixes this problem.