In content > design > configuration theme , I try to upload new logo by click on the Upload button. However, after select the image from PC, the ajax icon only spin a couple of times and then nothing happens, no file is selected for uploaded, no error in log file. I totally have no clue how to debug this error. I already tried to set permission 777 on localhost environment but it doesn't help.
The strange thing is product image upload works just fine. Any other section in admin that has file select field still works. Only this design section has problem.
Magento version 2.3.0 & Php 7.2
Best Answer
Ok, I found someone else who reported this error. Couldn't believe Magento team can release a stable version with this obvious bug, here is the fix https://github.com/magento/magento2/issues/18688 & https://github.com/magento/magento2/commit/ba69bfec127bed8c39c7d9e7b73d10b54449b158