Merge branch 'master' into bugfix/nan

src/app/views/menubar.tsx

@@ -380,7 +380,9 @@ export class MenuBar extends ContextedComponent<
               const inputElement = document.createElement("input");
               inputElement.type = "file";
               let file = null;
-              inputElement.accept = ["tmplt"].map((x) => "." + x).join(",");
+              inputElement.accept = ["tmplt", "json"]
+                .map((x) => "." + x)
+                .join(",");
               // eslint-disable-next-line
               inputElement.onchange = () => {
                 if (inputElement.files.length == 1) {

src/app/views/panels/widgets/fluentui_manager.tsx

@@ -1443,7 +1443,7 @@ export class FluentUIWidgetManager
             <ButtonRaised
               text="Import Template..."
               onClick={async () => {
-                const file = await showOpenFileDialog(["tmplt"]);
+                const file = await showOpenFileDialog(["tmplt", "json"]);
                 const str = await readFileAsString(file);
                 const data = JSON.parse(str);
                 const template = new ChartTemplate(data);

src/app/views/panels/widgets/manager.tsx

@@ -1120,7 +1120,7 @@ export class WidgetManager
           <ButtonRaised
             text="Import Template..."
             onClick={async () => {
-              const file = await showOpenFileDialog(["tmplt"]);
+              const file = await showOpenFileDialog(["tmplt", "json"]);
               const str = await readFileAsString(file);
               const data = JSON.parse(str);
               const template = new ChartTemplate(data);