src/vs/code/electron-sandbox/issue/issueReporterMain.ts/IssueReporter/validateSelectedExtension
class IssueReporter:	private validateSelectedExtension(): void {
		const extensionValidationMessage = this.getElementById('extension-selection-validation-error')!;
		const extensionValidationNoUrlsMessage = this.getElementById('extension-selection-validation-error-no-url')!;
		hide(extensionValidationMessage);
		hide(extensionValidationNoUrlsMessage);

		if (!this.issueReporterModel.getData().selectedExtension) {
			this.previewButton.enabled = true;
			return;
		}

		const hasValidGitHubUrl = this.getExtensionGitHubUrl();
		if (hasValidGitHubUrl) {
			this.previewButton.enabled = true;
		} else {
			this.setExtensionValidationMessage();
			this.previewButton.enabled = false;
		}
	}