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Slow Scrolling With sfRichTextBoxAdv

I'm using sfRichTextBoxAdv via ElementHost in a Winforms (VB.net) project. Seems to work fine except that scrolling is very slow. Using the scrollbar arrows it jumps a few pixels at a time with a half-second between jumps. Dragging the scrollbar thumb produces a hesitation followed by a half-page jump. The same problem occurs in the "Document Editor" sample project. The same .rtf file scrolls smoothly when opened in Libre Office. It's a small (5 pages) file with no graphics.

Is this an issue with the control? If so is there a workaround to get smoother scrolling?

Thanks -- AB

5 Replies

VM Venkatesan Mani Syncfusion Team February 13, 2017 10:38 AM UTC

Hi Alan, 
Thank you for contacting Syncfusion support. 
We have improved the scrolling responsiveness in our SfRichTextBoxAdv control and included this fix in our latest Essential Studio Volume 1, 2017. It is rolled out and is available for download under the following link. 
Kindly update to the latest version ( and test the scrolling responsiveness in our SfRichTextBoxAdv. Please get back to us, if you require any further assistance. 
Regards,  Venkatesan M. 

AB Alan Burkhart February 14, 2017 06:47 AM UTC

Installed the update. Scrolling still sputters a bit but is improved. In all honesty, the scrolling issue still makes the control unusable for a production project. Still needs work. Another issue exists with this update: Now the files have entire paragraphs replaced with empty space when scrolling. This seems to occur more when dragging the scrollbar thumb than when using the arrows. But it happens in both cases. I tried it with both .doc and .rtf files with same result.

VM Venkatesan Mani Syncfusion Team February 15, 2017 12:24 PM UTC

Hi Alan, 
Thank you for your update. 
Regarding scrolling performance: 
Currently, we have handled UI Virtualization in our SfRichTextBoxAdv control by default, to utilize optimal memory. Hence the content within view port of SfRichTextBoxAdv control will be rendered during initial load. While scrolling, the contents will be rendered dynamically when brought into viewport. 
Regarding the issue “paragraphs replaced with empty space when scrolling”:    
We can reproduce the mentioned issue in our SfRichTextBoxAdv control. A support incident to track the status of this issue and the feature (scrolling performance) has been created under your account. Please log on to our support website to check for further updates 
Venkatesan M. 

AS Andrei Sugeac replied to Venkatesan Mani December 8, 2021 10:14 AM UTC


Has the issue with the paragraphs being replaced with empty space been resolved?? I have the same issue with my sfrichtextboxadv and I would like to know what is the solution for it.

KG Kalaivannan Ganesan Syncfusion Team December 9, 2021 05:04 PM UTC

Hi Andrei,

Thanks for contacting Syncfusion support.

We have tried to reproduce the reported issue in the SfRichTextBoxAdv with V19.3.0.57. but the paragraphs are rendered properly on scrolling the document in both pages and continuous
layout mode.

Also created a sample to demonstrate the same which can be downloaded from the below location

So, please modify and share the sample with replication steps to reproduce the reported issue from our side.

Please let us know if you have any other questions.

Kalaivannan Ganesan

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