Issue
When using a Timer control to query a Calendar control value whilst having a Calendar picker open causes the Calendar control to stop working. For example, a Calendar control is hidden but is used as an input for the Timer to refresh a List View.
In the browser's Console tab, you will notice these Javascript errors:
Uncaught TypeError: Cannot read properties of null (reading 'textbox')
Uncaught TypeError: Cannot read properties of null (reading 'button')
Diagnosis
A bug has been logged to be fixed in the next major release.
Workaround
Here are the workarounds available:
1. Disable the Timer control
2. Remove the dependency on the Calendar control
- Add a change event for the calendar used in the timer and map the value to a parameter or a hidden data label. Use this control / parameter in the timer instead