Background and Purpose I Instructions

Background and Purpose

Overlapping objects that obstruct content can create reflow problems in the generated PDF document, can present ambiguities to the software,  and in some cases may cause the PDF not to be generated correctly.  This checkpoint allows the user to review each instance of overlapping objects to prevent these issues.


The Current Checkpoint displays a list of detected overlapping objects.

  1. Select each object from the list.
  2. Ensure that no content is obstructed by the object.
  3. If content is obstructed, either close CommonLook Office and change the design so that no content is obstructed, or group any objects that should overlap (you can add alternative text in the Text Tags checkpoint).

Picture of the CommonLook Office panel showing overlapping objects side by side with the PowerPoint Presentation.

For each instance of overlapping objects in which content is obstructed, the following options are available:

  • Group the objects (if you can). Each group will have a single tag in the output PDF.
  • Change the design so the objects no longer overlap. Each object will receive its own tag.
  • Leave the design as is. In the case in obstructed content, errors may occur. Some content belonging to one object may be tagged with another. Some content may become hidden in the physical view and still be readable in the logical view.

It is recommended that overlapping objects are grouped and that alternative text is provided for the group as a whole. See Adding Alternative Text in MS PowerPoint.

Key Tip: When objects are obstructed (hidden) by other objects, the PDF may not be generated correctly. If, when using CommonLook, the author allows overlapping of content, then the slides in question should be checked in the resulting PDF to make sure that they are generated correctly.  Should overlapping cause issues in the PDF, return to PowerPoint, move the obstructed text to a new text box, group the new textbox with the image, and recreate the PDF.

Guidelines and Standards

This checkpoint is relevant to the following regulations, guidelines and standards.

Document Published Scope Conformance Criteria
US Section 508 (USA) 2001 “Web-Based Information & Applications” Paragraphs (d)
W3C WCAG 2.0 2008 Web Content SC 1.3.2
ISO 14289 (PDF/UA) 2012 PDF Technology Section 7.1