I still don't know which version of UEStudio you use. I restored UEStudio v11.00.0.1011 from an archive, opened the tag list view, entered into the new file several words, selected one word, and double clicked on heading 2 in the tag list with HTML tags. The behavior is exactly as I already wrote in my previous post. The double clicked tag was still the selected tag in tag list. Also applying the tag on selected text with keyboard keeps the selected tag. There is no scroll up to first tag in tag list. In other words, I can't reproduce the issue you have on your computer with UES v11.00.0.1011. Therefore I have no solution for your problem as it does not occur on my computer.
It looks like you are writing webpages. So I was astonished to see that you captured your screen with PrtScr (entire desktop) instead of Alt+PrtScr (just active window). There are also free applications like
IrfanView or
HardCopy making it very easy to define which part of screen should be captured (all monitors, active monitor, foreground window, just client area of foreground window, user defined rectangle, object/window selected by mouse, fixed rectangle on screen). And a webpage writer should also know the advantages and disadvantages of the common image formats for webpages:
JPEG and
PNG. PNG supports true color images like JPEG, but uses a lossless compression (no pixel noise as JPEG produces on lossy compression) and produces in general for screen shots with large areas with same color and regular image patterns (the text) smaller files than JPEG. PNG was designed preliminary for webpages and is an image format supported by all applications being able to create or just display images. PNG is used for graphics, JPEG for photos. Next time use for your screen shots Alt+PrtScr and save as PNG file.