The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fbb92aa722a4723c69c07de6163c3725b653c290

commit fbb92aa722a4723c69c07de6163c3725b653c290
Author: einbinder <einbinder@chromium.org>
Date: Thu Dec 08 01:57:23 2016

DevTools: Use TextPrompt for FilterBar instead of input element

BUG= 670550 

Review-Url: https://codereview.chromium.org/2545983002
Cr-Commit-Position: refs/heads/master@{#437134}

[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/LayoutTests/http/tests/inspector/network/network-filters.html
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/network/NetworkLogView.js
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/timeline/timelinePanel.css
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/ui/FilterBar.js
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/ui/TextPrompt.js
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/ui/filter.css
[modify] https://crrev.com/fbb92aa722a4723c69c07de6163c3725b653c290/third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css

+1 

Also try typing "lang" into the filterbar. Then backspace it away.

When it gets to 'la' it brings up a floating element suggesting 'larger-than' but it doesn't go away if you keep backspacing. You need to select all the text and delete it at once.