Spyder 4 extremely slow writing on text editor in MacOS Big Sur

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

When I write in the code editor in Spyder, letters are displayed extremely slow, I mean I can write the following: “jsdhfakljhdsfjkhsdkjhfkjdshfjkdshkjfh” and it’ll take about 5-8 seconds in show it in the text editor.

What steps reproduce the problem?

1. The problem only affects to Spyder>3.3.6 in MacOS Big Sur on a clean Anaconda3 installation.

Versions

• Spyder version: spyder=4.2.0
• Python version: python=3.8.5
• Qt version: qt=5.9.7
• PyQt version: pyqt=5.9.2
• Operating System name/version: MacOS Big Sur 11.1

Dependencies

Mandatory:

applaunchservices >=0.1.7 : 0.2.1 (OK) atomicwrites >=1.2.0 : 1.4.0 (OK) chardet >=2.0.0 : 4.0.0 (OK) cloudpickle >=0.5.0 : 1.6.0 (OK) diff_match_patch >=20181111 : 20200713 (OK) intervaltree >=3.0.2 : 3.1.0 (OK) IPython >=4.0 : 7.19.0 (OK) jedi =0.17.2 : 0.17.2 (OK) jsonschema >=3.2.0 : 3.2.0 (OK) nbconvert >=4.0 : 6.0.7 (OK) numpydoc >=0.6.0 : 1.1.0 (OK) parso =0.7.0 : 0.7.0 (OK) pexpect >=4.4.0 : 4.8.0 (OK) pickleshare >=0.4 : 0.7.5 (OK) psutil >=5.3 : 5.7.2 (OK) pygments >=2.0 : 2.7.3 (OK) pylint >=1.0 : 2.6.0 (OK) pyls >=0.36.1;<1.0.0 : 0.36.2 (OK) pyls_black >=0.4.6 : 0.4.6 (OK) pyls_spyder >=0.1.1 : 0.3.0 (OK) qdarkstyle >=2.8 : 2.8.1 (OK) qtawesome >=0.5.7 : 1.0.1 (OK) qtconsole >=4.7.7 : 4.7.7 (OK) qtpy >=1.5.0 : 1.9.0 (OK) rtree >=0.8.3 : 0.9.4 (OK) setuptools >=39.0.0 : 51.0.0.post20201207 (OK) sphinx >=0.6.6 : 3.4.1 (OK) spyder_kernels >=1.10.0;<1.11.0 : 1.10.1 (OK) three_merge >=0.1.1 : 0.1.1 (OK) watchdog >=0.10.3 : 0.10.4 (OK) zmq >=17 : 20.0.0 (OK)

Optional:

cython >=0.21 : None (NOK) matplotlib >=2.0.0 : None (NOK) numpy >=1.7 : None (NOK) pandas >=1.1.1 : None (NOK) scipy >=0.17.0 : None (NOK) sympy >=0.7.3 : None (NOK)

[leet0rz]

Still an issue in windows. it lags a lot.

[brilund]

Still an issue on Mac.