Design Preview and Testing Results pane should be resizable

Describe the bug In the design and test tabs, the right-most pane (preview and test results) are not resizable. In the debug tab, we can see that the three panels can be resized independently.

Expected behavior All three panels on each tab should be resizable independently.

Screenshots

Desktop (please complete the following information):

Version: Insomnia Designer 2020.4.0-beta.6
Release date: 02/09/2020
OS: Darwin x64 19.6.0
Electron: 9.1.1
Node: 12.14.1
V8: 8.3.110.13-electron.0
Architecture: x64
node-libcurl: libcurl/7.69.1 OpenSSL/1.1.1g zlib/1.2.11 brotli/1.0.7 libidn2/2.1.1 libssh2/1.9.0 nghttp2/1.41.0

INS-54

Related: https://github.com/Kong/insomnia/issues/2584

[simplywondrous]

Hello! The PR’s going well - the Test Results pane is now resizable!

Before I clean it up more, I have a question about how to proceed, written in the PR if you could take a look!

[develohpanda]

Wow, nice sleuthing! It might be useful to add a line describing what you had to do differently with WSL 2 into the README, for anybody else that faces the same issue.

Also, thanks for being generally friendly, helpful, and responsive. As a beginner, working on open source is quite intimidating, so I really appreciate it!

No problem! 🤗 OSS is not some holy grail where every PR is perfect first time. It’s still, always, a collaborative process and an opportunity to learn. We all start somewhere; I’m glad you chose this project!

Ideally, generic and reusable logic would be amazing (there might be a fourth tab in the future 👀). If that is a decent chunk of work though, then it would be good to weigh up the different options. Admittedly I have not investigated this issue directly, but I’ll let you work through it. 😃

Is it okay for me to open a draft PR starting with the most straightforward way, and then code reviewing and iterating from there?

Of course! That’s an efficient way to go about it.