When you double-click on the column header resize handle to auto-resize the column to fit the contents, it does the auto-fit, then it changes the currently selected log file or filter.

If I have this in the Log Files & Filters panel:

File 1
File 2
  Search 1
     Search 2
Merged Log Files
   Search 3

These are the scenarios I'm able to repro the bug in:
1) Search 2 is active, then double-click to auto-fit, the active file will change to the top-most parent, File 2.  If I double-click to auto-fit again, it resizes without changing files.
2) Search 3 is active, then double-click to auto-fit, the active file will change to the top-most parent, Merged Log Files.  Double-click to auto-fit again, the active file will change to File 1.

Expected result: The active file does not change when columns are auto-resized.

Thanks for bringing this issue to our attention. 

I have been able to recreate the issue and have implemented a fix which will be available in the next release.  Hopefully we will have v3.0.18 available as a BETA release early next week.

In the meantime, I would suggest you resize the columns using drag / drop rather than double-click.

Thanks again!

Toby