The only problem I ever faced with SDF(only using Webstorm GUI) is when you clone a project from Git, the external libraries are not added to the project, looks like WebStorm does not recognize you are cloning an SDF Project.

what do you mean by external libraries not added to the project? I'm not sure how SDF plays into that, except as controlling what gets copied to netsuite on deployment (i.e. not involved in git clone)

When you create a new SDF Project through WebStorm (UI) you get an SDF Project folder structure and external libraries which are the ones handling the code completion, SuiteScript 1.0 and SuiteScript 2.0. Now if you commit/merge that to a Git Repo and later on somebody else or your clone the project in another computer where you don’t have the original project folder created by WebStorm… Webstorm does not know or notice you are cloning and SDF project and your folder structure (for example empty Objects folder) and external libraries are gone…

its probably the fact that the project was created with an older version of the plugin you would likely have to edit the .iml in the .idea folder. for the latest version the two lines should look like this

<root url="jar://$APPLICATION_PLUGINS_DIR$/com.netsuite.ide.webstorm.app/lib/com.netsuite.ide.webstorm.app_2019.1.2.jar!/library/SuiteScript_1_0" />
   <root url="jar://$APPLICATION_PLUGINS_DIR$/com.netsuite.ide.webstorm.app/lib/com.netsuite.ide.webstorm.app_2019.1.2.jar!/library/SuiteScript_2_0" />

if it isn't that then I guess the project is actually storing the $APPLICATION_PLUGINS_DIR$ within it

Ah, since I don't rely on that plugin for code completion I guess I never noticed. We use TypeScript and a combination of NFT and @hitc/netsuite-types declarations