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How many sensor icons are loaded immediately in the web interface and how can I change this number?



When I quickly drag the scrollbar next to the device tree downward it takes a few moments before the sensor icons in the device tree are displayed.

Why is this? Can I change this behavior?

customize device-tree javascript prtg sensor-display sensors slow web-interface

Created on Oct 5, 2011 7:17:02 AM by  Dirk Paessler [Founder Paessler AG] (11,025) 3 6

Last change on Mar 28, 2014 2:48:07 PM by  Gerald Schoch [Paessler Support]

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Accepted Answer



This article applies to PRTG Network Monitor 13.2.3 through 17.3.33

Device Tree View in PRTG: Number of Instantly Loaded Sensors

Important note: The current customization approach is unsupported and deprecated as of versions 17.3.34/17.4.35. This customization no longer works. For more details, see How can I re-brand and customize the PRTG web interface using CSS and Javascript?

As of PRTG version 9, the device tree has two display modes:

  • If there are less than 1000 sensors to display, all sensor icons are loaded and displayed immediately and you will not get an additional scrollbar next to the device tree.
  • If there are more than 1000 sensors to display, only the first screenpage is loaded and rendered. As soon as you scroll down, the next page is loaded and rendered (which may take a moment). For large installation this approach requires less CPU and network resources.

Why did we do it like that?

This concept allows the user to either quickly move through smaller trees (or sub-trees) or to efficiently work even with huge installations with thousands of sensors.

The second behavior may feel unusual to users of the deprecated PRTG version 8, but it is actually less resource intensive than the old technology.

Can I change this behavior?


In our own testing we found that the limit of 1000 sensors worked fine for both worlds. But there may be situations were a higher or lower limit is desired by the user. So we made it editable.

For PRTG 13.2.3 or later you can change the limit by editing the file scripts_custom.js in the folder \PRTG Network Monitor\webroot\javascript.

Open the file in a text editor and add this line to the file:

_Prtg.Core.objects.maxSensorFullSize=2000; //default is 1000

Then reload your browser window completely with the F5 key (it may be necessary to close the browser and restart it to get around caching).

You can play around with this value until it fits your needs.

Note: For PRTG 9 through 12 you can change the limit by editing the file customerscripts.js in the folder \PRTG Network Monitor\website\javascript.


You can also edit the width of the column used for the display of groups/devices

Created on Oct 5, 2011 7:34:19 AM by  Dirk Paessler [Founder Paessler AG] (11,025) 3 6

Last change on Mar 22, 2018 12:21:44 PM by  Brandy Greger [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.