diff --git a/dist/index.js b/dist/index.js
index 517cee7..8e87d00 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -169,6 +169,7 @@ class IssueContentParser {
         const contentLines = issue.body?.split("\n") ?? [];
         return contentLines
             .filter(x => this.isTaskListLine(x))
+            .map(x => x.substring(6))
             .map(x => (0, utils_1.parseIssueUrl)(x))
             .filter((x) => x !== null);
     }
@@ -194,6 +195,9 @@ class IssueContentParser {
             ...contentLines.slice(sectionEndIndex !== -1 ? sectionEndIndex : contentLines.length),
         ].join("\n");
     }
+    isIssueClosed(issue) {
+        return issue.state === "closed";
+    }
     isIssueContentIdentical(issue, newIssueContent) {
         // GitHub automatically replace "\n" to "\r\n" line endings when issue body is modified through GitHub UI.
         // Replace "\r\n" to "\n" before comparing content to avoid unnecessary issue updates.
@@ -272,8 +276,16 @@ const run = async () => {
         const issueContentParser = new issue_content_parser_1.IssueContentParser();
         const mermaidRender = new mermaid_render_1.MermaidRender(inputs.includeLegend);
         const rootIssue = await githubApiClient.getIssue(inputs.rootIssue);
+        if (issueContentParser.isIssueClosed(rootIssue)) {
+            core.info("Skipping generation of mermaid diagram because issue is closed");
+            return;
+        }
         const rootIssueTasklist = issueContentParser.extractIssueTasklist(rootIssue);
         core.info(`Found ${rootIssueTasklist.length} work items in task list.`);
+        if (rootIssueTasklist.length === 0) {
+            core.info("Skipping generation of mermaid diagram because there is no issues in tasklist");
+            return;
+        }
         core.info("Building dependency graph...");
         const graphBuilder = new graph_builder_1.GraphBuilder(inputs.includeFinishNode);
         for (const issueRef of rootIssueTasklist) {
@@ -435,11 +447,9 @@ ${renderedGraphIssues}
 `;
     }
     renderIssue(issue) {
-        let result = `${issue.nodeId}("${issue.getWrappedTitle()}"):::${issue.status};`;
-        if (issue.url) {
-            result += `\nclick ${issue.nodeId} href "${issue.url}" _blank;`;
-        }
-        return result;
+        const title = issue.getWrappedTitle();
+        const linkedTitle = issue.url ? `<a href='${issue.url}' style='text-decoration:none;color: inherit;'>${title}</a>` : title;
+        return `${issue.nodeId}("${linkedTitle}"):::${issue.status};`;
     }
     renderDependencies(dependencies) {
         const renderedDependencies = dependencies.map(x => this.renderDependency(x)).join("\n");
@@ -467,10 +477,10 @@ exports.MermaidRender = MermaidRender;
 
 Object.defineProperty(exports, "__esModule", ({ value: true }));
 exports.parseIssuesUrls = exports.parseIssueUrl = void 0;
-const issueUrlRegex = /github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)/i;
-const issueUrlsRegex = new RegExp(issueUrlRegex, "ig");
+const issueUrlRegex = /^https:\/\/github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)$/i;
+const issueUrlsRegex = /github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)/gi;
 const parseIssueUrl = (str) => {
-    const found = str.match(issueUrlRegex);
+    const found = str.trim().match(issueUrlRegex);
     if (!found) {
         return null;
     }
diff --git a/src/issue-content-parser.ts b/src/issue-content-parser.ts
index d6f8f86..8b05ab7 100644
--- a/src/issue-content-parser.ts
+++ b/src/issue-content-parser.ts
@@ -7,6 +7,7 @@ export class IssueContentParser {
 
         return contentLines
             .filter(x => this.isTaskListLine(x))
+            .map(x => x.substring(6))
             .map(x => parseIssueUrl(x))
             .filter((x): x is GitHubIssueReference => x !== null);
     }
@@ -41,6 +42,10 @@ export class IssueContentParser {
         ].join("\n");
     }
 
+    public isIssueClosed(issue: GitHubIssue): boolean {
+        return issue.state === "closed";
+    }
+
     public isIssueContentIdentical(issue: GitHubIssue, newIssueContent: string) {
         // GitHub automatically replace "\n" to "\r\n" line endings when issue body is modified through GitHub UI.
         // Replace "\r\n" to "\n" before comparing content to avoid unnecessary issue updates.
diff --git a/src/main.ts b/src/main.ts
index 7e387d5..b81185c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -14,9 +14,17 @@ const run = async (): Promise<void> => {
         const mermaidRender = new MermaidRender(inputs.includeLegend);
 
         const rootIssue = await githubApiClient.getIssue(inputs.rootIssue);
-        const rootIssueTasklist = issueContentParser.extractIssueTasklist(rootIssue);
+        if (issueContentParser.isIssueClosed(rootIssue)) {
+            core.info("Skipping generation of mermaid diagram because issue is closed");
+            return;
+        }
 
+        const rootIssueTasklist = issueContentParser.extractIssueTasklist(rootIssue);
         core.info(`Found ${rootIssueTasklist.length} work items in task list.`);
+        if (rootIssueTasklist.length === 0) {
+            core.info("Skipping generation of mermaid diagram because there is no issues in tasklist");
+            return;
+        }
 
         core.info("Building dependency graph...");
         const graphBuilder = new GraphBuilder(inputs.includeFinishNode);
diff --git a/src/mermaid-render.ts b/src/mermaid-render.ts
index 3afdd96..590f2a3 100644
--- a/src/mermaid-render.ts
+++ b/src/mermaid-render.ts
@@ -61,12 +61,9 @@ ${renderedGraphIssues}
     }
 
     private renderIssue(issue: MermaidNode): string {
-        let result = `${issue.nodeId}("${issue.getWrappedTitle()}"):::${issue.status};`;
-        if (issue.url) {
-            result += `\nclick ${issue.nodeId} href "${issue.url}" _blank;`;
-        }
-
-        return result;
+        const title = issue.getWrappedTitle();
+        const linkedTitle = issue.url ? `<a href='${issue.url}' style='text-decoration:none;color: inherit;'>${title}</a>` : title;
+        return `${issue.nodeId}("${linkedTitle}"):::${issue.status};`;
     }
 
     private renderDependencies(dependencies: GraphEdge[]): string {
diff --git a/src/utils.ts b/src/utils.ts
index 74c38bd..b0f48d9 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -3,11 +3,11 @@ import { GitHubIssueReference } from "./models";
 // Analogue of TypeScript "Partial" type but for null values
 export type NullablePartial<T> = { [P in keyof T]: T[P] | null | undefined };
 
-const issueUrlRegex = /github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)/i;
-const issueUrlsRegex = new RegExp(issueUrlRegex, "ig");
+const issueUrlRegex = /^https:\/\/github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)$/i;
+const issueUrlsRegex = /github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)/gi;
 
 export const parseIssueUrl = (str: string): GitHubIssueReference | null => {
-    const found = str.match(issueUrlRegex);
+    const found = str.trim().match(issueUrlRegex);
     if (!found) {
         return null;
     }
diff --git a/tests/utils.test.ts b/tests/utils.test.ts
index 61f38b5..a6c65d6 100644
--- a/tests/utils.test.ts
+++ b/tests/utils.test.ts
@@ -31,15 +31,8 @@ describe("parseIssueUrl", () => {
         expect(actual).toStrictEqual({ repoOwner: "actions", repoName: "setup-node", issueNumber: 5663 });
     });
 
-    it("parses correct issue url with task list marker", () => {
-        const actual = parseIssueUrl("- [ ] https://github.com/actions/setup-node/issues/5663");
-        expect(actual).toStrictEqual({ repoOwner: "actions", repoName: "setup-node", issueNumber: 5663 });
-    });
-
-    it("parses correct issue url if more than one issue in input line", () => {
-        const actual = parseIssueUrl(
-            "- [ ] https://github.com/actions/setup-node/issues/5663, https://github.com/actions/setup-node/issues/5665"
-        );
+    it("parses correct issue url with trailing spaces", () => {
+        const actual = parseIssueUrl(" https://github.com/actions/setup-node/issues/5663");
         expect(actual).toStrictEqual({ repoOwner: "actions", repoName: "setup-node", issueNumber: 5663 });
     });