The yellow frame blinks as shown in mp4. It's annoying and isn't good to the eyes.

OMG, request too large. I can't upload mp4 /(ㄒoㄒ)/~~

1. What OS and for Windows/Mac, version?
2. What Python release and from where and how installed?
   If not latest release of x.y, where x.y >= 3.7, consider upgrading.
3. Tcl/tk version (see Help => About IDLE?
4. How start IDLE?
5. What is a the minimum action needed to exhibit the behavior.  Copy and paste minimum code.
6. Describe behavior with more detail.  What you wrote is nothing like anything that should happen (which is why you report it), so it is hard to imagine.

Each  '(' and ')' in an argument string such as in f('()(()()((((())))))))))))))') causes a blink.  Ditto with a comment withing the call.  A related bug is that any unquoted '(', as when one enters f((a+b)*c), dismisses the tip. 

Proposed partial solution: before displaying a tip, record the opening index (before the opening '(').  When there is an opening index, and '(' is keyed, ignore it; no parsing.  When the tip is closed (properly), removed the open index.  I believe paren matching would work properly.

The cause of blinks for ')' in strings and comments would need to be found and remedied.

I agree that this should be improved.

Terry, on the technical side, IDLE already has good tools for parsing the current code line/block and figuring out whether the cursor is in a string, a comment or parentheses. This should be possible to solve in a robust way without writing any new parsing logic.

I'll try to take a look at this soon.

> OMG, request too large. I can't upload mp4

You can try to reduce the video's resolution and/or framerate in order to reduce its size.

Usually screen captures are taken at high resolution and framerates by default, making the resulting video files very large, which is a sensible default but not great for attaching to bug reports.

Confirmed on latest master on macOS 10.15.5 with Tcl/Tk 8.6.10.

See PR GH-20910 with a fix.

New changeset da7bb7b4d769350c5fd03e6cfb16b23dc265ed72 by Tal Einat in branch 'master':
bpo-40511: Stop unwanted flashing of IDLE calltips (GH-20910)
https://github.com/python/cpython/commit/da7bb7b4d769350c5fd03e6cfb16b23dc265ed72

New changeset 79e9f06149f92798a8e11e3f1c62dad171312ab3 by Miss Skeleton (bot) in branch '3.9':
bpo-40511: Stop unwanted flashing of IDLE calltips (GH-20910)
https://github.com/python/cpython/commit/79e9f06149f92798a8e11e3f1c62dad171312ab3

New changeset 1341582e165841810e2fbf89e23be0e92b4a9fdd by Miss Skeleton (bot) in branch '3.8':
bpo-40511: Stop unwanted flashing of IDLE calltips (GH-20910)
https://github.com/python/cpython/commit/1341582e165841810e2fbf89e23be0e92b4a9fdd

wyz, thank you for the report.  It should be fixed now.

Thanks! :D