Adding a custom tab with an action of customurl, and setting it to open in a new window may result in an error message being displayed.
On selecting the custom tab, the script error below will appear either onscreen, or in the developer console:
Message: Unable to get property 'SelectNewWin' of undefined or null reference
The code used to call a new window references an IFrame that was removed in v7.2.
This issue has been resolved in Sage CRM 7.3.
The issue can be worked around by following the steps below:
1: Create a new block on the entity affected. Create it as a Custom Content block.
2: Enter the following in the Contents area, replacing the highlighted area with your desired URL:
On your custom tab, change the action from customurl to runblock, and enter the name of your custom tab.
The second line of the above script redirects the page back to the calling tab in CRM. This can be changed, should requirements so dictate.