Visual shift when using "Select All" in Contents Pane after using Merge Pages

[rakunavi]

Hello all,

I noticed a behavior where selecting base content via the "Select All" function in the Contents Pane shows a different visual selection compared to the actual base content layout after merging pages.

• figure.png

In the attached video, a 6-page sample document is merged vertically into a single page.
I applied the "Select All" function in the Contents Pane both before and after merging. Please note that after the merge, the highlighted selection somehow shifts upward, creating a discrepancy with the actual placement of the base content.

• Animation1.gif

• sample.pdf

The sample file was created by combining standard PDF-XChange Editor features in the following steps. Since I’m using the “End User License Agreement” file (PXCLicense.pdf) that comes with PDF-XChange Editor, anyone should be able to create the same file.

1. Merge 3 pages horizontally into a single page using the "Merge Pages" feature.
2. Insert a blank page at the very end.
3. Reduce the height of the inserted blank page to 50% using the "Resize Pages" feature.
4. Duplicate all pages to make 2 sets using the "Duplicate Pages" feature, resulting in 6 pages in total.
5. Normalize the pages using the "Normalize Pages" feature.

For your reference, the creation process is also shown in the video:

• Animation2.gif

Any insights or assistance on this issue would be greatly appreciated.

Best regards,
rakunavi

- PDF-XChange Editor PRO Version: 11.0.0
- OS Version: Windows 11 Pro / Home 25H2 Build 26200.8457
- PC Model: GMKtec Nucbox M7 Pro with HUION Kamvas Pro 19 / Lenovo IdeaPad C340-15IWL

[PHK]

Hi, Raknavi, thank you for posting on this subject which has been bothering me for a long time. As I think you know, I do a lot of page-merging. This sometimes results in having content show 'all over the place' as in your illustrative anim. The more you merge and re-merge the more skewed things can become.

But I have to admit that I am merging pages less than I used to partially to avoid this problem. Much of my page merging is adding incremental data to a broad canvas. For instance, adding new monthly statements to a large sheet over several months and years of statements. Increasingly, I am doing this by copying in the Content panel data pages to be added to the broad sheet and pasting them in as Stamps which I then Flatten. I will either merge the pages of the to-be-added pages before copying or pasting page-by-page depending on which method seems more appropriate for the content. This works very well with good flexibility and minimal file bloat.

But I must add that in a case like your anim example where you are merging many similar-sized pages of a source file, I find it best to do a little thoughtful resizing of the pages before merging so that no splitting and re-merging is necessary.

[rakunavi]

Hello PHK, thank you for your input.

But I must add that in a case like your anim example where you are merging many similar-sized pages of a source file, I find it best to do a little thoughtful resizing of the pages before merging so that no splitting and re-merging is necessary.

It seems that each merge adds another layer to the XForm, and once it forms a nested structure of two or more levels, problems are more likely to occur. As proof of this, if I flatten the XForm hierarchy in the Contents pane, the issue does not occur as long as I only perform a single merge afterward.

• figure.png
  
  
  Animation.gif

• sample2.pdf

Of course, if I continue to merge under the same conditions as this time, the problem reoccurs... By the way, I previously posted a workaround for flattening the XForm layers here:

• Re: In Build 406, range selection no longer works when Object Editing → Shape is set
  viewtopic.php?p=200122#p200122

Although the PDF specification itself does not seem to impose a limit on XForm nesting levels, given the complexity involved in processing them, it might be safer to keep XForm hierarchies to a single level if possible in modern PDF applications.

Practices that avoid unnecessarily increasing XForm layers, such as using the Stamp tool as you pointed out, may indeed be the most practical workaround.

Best regards,
rakunavi

[Sean - PDF-XChange]

Hi Rakunavi/Willy,

Thanks for the detailed report - I have let the team know.

Kind regards,

[PHK]

...

It seems that each merge adds another layer to the XForm, and once it forms a nested structure of two or more levels, problems are more likely to occur. As proof of this, if I flatten the XForm hierarchy in the Contents pane, the issue does not occur as long as I only perform a single merge afterward.
...
Of course, if I continue to merge under the same conditions as this time, the problem reoccurs.
...
Although the PDF specification itself does not seem to impose a limit on XForm nesting levels, given the complexity involved in processing them, it might be safer to keep XForm hierarchies to a single level if possible in modern PDF applications.
...

Yes, rakunavi, I am a bit put off by the multiplication of XForm nesting levels and the anomolous placements of content layers as you illustrate. What I particularly don't like is the that it seems that a fair amount of extraneous content goes along with every new merge. This seems to be particularly true if one does not elect to remove content outside the crop box in the Crop pages tool. Hence, my increasing use of copying and pasting new pages or areas of new pages as a way of adding new content to pre-existing pages or sheets. N. B. I usually delete the new file that was the downloaded (or scanned) medium for the new content once I've done the above, thereby mimimizing dreaded file bloat.

[Sean - PDF-XChange]

Update - a ticket has been made in relation to this issue:

Ticket #7839: Visual Shift when Using "Select All" in Contents Pane after Merging Pages

Kind regards,