10. A computer system comprising: a processor; and a memory storing instructions that, when executed by the processor, cause the processor to: detect a request on a client device to embed a folder in a document displayed on the client device, the document having visible document content and the folder containing one or more content items, wherein the folder and the one or more content items are synchronized with a content management system; designate a region of the document as a preview region for the folder; generate content item preview for the one or more content items; select, for display in the preview region, a subset of the generated content item previews; display, within the preview region, the selected subset of content item previews; receive a scrolling input to the client device; in response to the scrolling input having a vertical direction, scroll the document content including the preview region, in the direction of the scrolling input; and in response to the scrolling input having a horizontal direction, irrespective of a location of the received horizontal scrolling input: scroll out of the preview region a number of content item previews; and scroll into the preview region the number of additional generated content item previews not included in the displayed subset of the generated content item previews, without scrolling the document.
10. A computer system comprising: a processor; and a memory storing instructions that, when executed by the processor, cause the processor to: detect a request on a client device to embed a folder in a document displayed on the client device, the document having visible document content and the folder containing one or more content items, wherein the folder and the one or more content items are synchronized with a content management system; designate a region of the document as a preview region for the folder; generate content item preview for the one or more content items; select, for display in the preview region, a subset of the generated content item previews; display, within the preview region, the selected subset of content item previews; receive a scrolling input to the client device; in response to the scrolling input having a vertical direction, scroll the document content including the preview region, in the direction of the scrolling input; and in response to the scrolling input having a horizontal direction, irrespective of a location of the received horizontal scrolling input: scroll out of the preview region a number of content item previews; and scroll into the preview region the number of additional generated content item previews not included in the displayed subset of the generated content item previews, without scrolling the document. 11. The computer system of claim 10 , wherein the processor is further caused to: detect a request to add a new content item to the folder; receive an updated preview of the folder; and responsive to the preview region being in a visible portion of the document, display the updated preview of the folder in the preview region.