The alerts tab shows alerts generated by Burp's tools. This information may be useful to troubleshoot network connection or other problems.
If the same alert is generated more than once in succession, the alerts are consolidated into a single entry in the table, with a counter showing the number of times the alert was generated.
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This release fixes a bug which was introduced in the v1.5rc2 release, and which caused the active scan checks for XSS to fail to execute in some situations