diff --git a/Changelog.md b/Changelog.md
index ff0ad39f09..1fa4bbbbe8 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -16,6 +16,7 @@
 - Add pagination to Admin Users table for performance (#7997)
 
 ### 🐛 Bug fixes
+- Fixed bug where clicking a file link in the annotations tab would show a blank or oversized error for PDF files (#8017)
 - Fixed bug where clicking MarkUs logo in navbar on mobile would open the sidebar instead of redirecting to courses page (#7990)
 - Fixed bug where merge commits were incorrectly flagged as making a new assignment submission when no assignment files were changed (#7988)
 - Fixed shift+up/shift+down keybinding being suppressed when a criterion input had focus; active criterion now scrolls into view when navigated to via keyboard (#7989)
diff --git a/app/javascript/Components/Result/left_pane.jsx b/app/javascript/Components/Result/left_pane.jsx
index a86b11582d..47162ebe0b 100644
--- a/app/javascript/Components/Result/left_pane.jsx
+++ b/app/javascript/Components/Result/left_pane.jsx
@@ -55,11 +55,24 @@ export class LeftPane extends React.Component {
     }
   }
 
+  getFileTypeById = (fileData, id) => {
+    for (const file of fileData.files) {
+      if (file[1] === id) return file[2];
+    }
+    for (const dir of Object.values(fileData.directories || {})) {
+      const type = this.getFileTypeById(dir, id);
+      if (type !== null) return type;
+    }
+    return null;
+  };
+
   // Display a given file. Used to changes files from the annotations panel.
   selectFile = (file, submission_file_id, focus_line, annotation_focus) => {
+    const type = this.getFileTypeById(this.props.submission_files, submission_file_id);
     this.submissionFilePanel.current.selectFile(
       file,
       submission_file_id,
+      type,
       focus_line,
       annotation_focus
     );
diff --git a/app/javascript/Components/__tests__/left_pane.test.jsx b/app/javascript/Components/__tests__/left_pane.test.jsx
new file mode 100644
index 0000000000..a83d3cb9fd
--- /dev/null
+++ b/app/javascript/Components/__tests__/left_pane.test.jsx
@@ -0,0 +1,140 @@
+import React from "react";
+import {render} from "@testing-library/react";
+import {LeftPane} from "../Result/left_pane";
+import {renderInResultContext} from "./result_context_renderer";
+
+jest.mock("../Result/annotation_panel", () => ({AnnotationPanel: () => <div />}));
+jest.mock("../Result/feedback_file_panel", () => ({FeedbackFilePanel: () => <div />}));
+jest.mock("../Result/remark_panel", () => ({RemarkPanel: () => <div />}));
+jest.mock("../test_run_table", () => ({TestRunTable: () => <div />}));
+jest.mock("../Result/submission_file_panel", () => {
+  const React = require("react");
+  const MockSubmissionFilePanel = React.forwardRef((props, ref) => {
+    React.useImperativeHandle(ref, () => ({selectFile: jest.fn()}));
+    return null;
+  });
+  MockSubmissionFilePanel.displayName = "MockSubmissionFilePanel";
+  return {SubmissionFilePanel: MockSubmissionFilePanel};
+});
+
+const flatFileData = {
+  files: [
+    ["report.pdf", 1, "pdf"],
+    ["notes.txt", 2, "text"],
+  ],
+  directories: {},
+  name: "",
+  path: [],
+};
+
+const nestedFileData = {
+  files: [["root.pdf", 1, "pdf"]],
+  directories: {
+    subdir: {
+      files: [["image.png", 2, "image"]],
+      directories: {
+        nested: {
+          files: [["data.csv", 3, "text"]],
+          directories: {},
+          name: "nested",
+          path: ["subdir", "nested"],
+        },
+      },
+      name: "subdir",
+      path: ["subdir"],
+    },
+  },
+  name: "",
+  path: [],
+};
+
+const basicProps = {
+  loading: false,
+  allow_remarks: false,
+  annotation_categories: [],
+  annotations: [],
+  assignment_remark_message: "",
+  update_overall_comment: jest.fn(),
+  can_run_tests: false,
+  detailed_annotations: false,
+  enable_test: false,
+  feedback_files: [],
+  instructor_run: false,
+  overall_comment: "",
+  past_remark_due_date: false,
+  released_to_students: false,
+  remark_due_date: null,
+  remark_overall_comment: "",
+  remark_request_text: "",
+  remark_request_timestamp: null,
+  remark_submitted: false,
+  revision_identifier: "1",
+  submission_files: flatFileData,
+  student_view: false,
+  newAnnotation: jest.fn(),
+  addExistingAnnotation: jest.fn(),
+  editAnnotation: jest.fn(),
+  removeAnnotation: jest.fn(),
+  rmd_convert_enabled: false,
+};
+
+describe("LeftPane", () => {
+  describe("getFileTypeById", () => {
+    let leftPaneRef;
+
+    beforeEach(() => {
+      leftPaneRef = React.createRef();
+      renderInResultContext(<LeftPane ref={leftPaneRef} {...basicProps} />);
+    });
+
+    it("returns the file type for a file at the root level", () => {
+      expect(leftPaneRef.current.getFileTypeById(flatFileData, 1)).toBe("pdf");
+      expect(leftPaneRef.current.getFileTypeById(flatFileData, 2)).toBe("text");
+    });
+
+    it("returns the file type for a file in a nested subdirectory", () => {
+      expect(leftPaneRef.current.getFileTypeById(nestedFileData, 2)).toBe("image");
+      expect(leftPaneRef.current.getFileTypeById(nestedFileData, 3)).toBe("text");
+    });
+
+    it("returns null when no file with the given id exists", () => {
+      expect(leftPaneRef.current.getFileTypeById(flatFileData, 3)).toBeNull();
+    });
+  });
+
+  describe("selectFile", () => {
+    it("passes the file type for a file at the root level", () => {
+      const leftPaneRef = React.createRef();
+      renderInResultContext(
+        <LeftPane ref={leftPaneRef} {...basicProps} submission_files={flatFileData} />
+      );
+
+      leftPaneRef.current.selectFile("report.pdf", 1, undefined, 42);
+
+      expect(leftPaneRef.current.submissionFilePanel.current.selectFile).toHaveBeenCalledWith(
+        "report.pdf",
+        1,
+        "pdf",
+        undefined,
+        42
+      );
+    });
+
+    it("passes the correct file type for a file in a nested subdirectory", () => {
+      const leftPaneRef = React.createRef();
+      renderInResultContext(
+        <LeftPane ref={leftPaneRef} {...basicProps} submission_files={nestedFileData} />
+      );
+
+      leftPaneRef.current.selectFile("subdir/image.png", 2, undefined, 42);
+
+      expect(leftPaneRef.current.submissionFilePanel.current.selectFile).toHaveBeenCalledWith(
+        "subdir/image.png",
+        2,
+        "image",
+        undefined,
+        42
+      );
+    });
+  });
+});