Highlight occurrences of selected text sometimes doesn't work

Problem

When a specific text/code in a file is selected, all occurrences of the same text are highlighted. Sometimes this functionality doesn't work as expected. Especially when there are a lot of occurrences in a large source file.

Cause

Note that when more than 50 instances of the selection are found, they will not be highlighted. A small number of highlights can be useful, while many highlights are mostly perceived as noise.

Resolution

This limit is configurable in the registry with the editor.highlight.selected.text.max.occurrences.threshold key.

To acces the registry, press Shift key two times (opens Search Everywhere) > type Registry.. > find the mentioned key and disable it > Close > Restart IDE.