I&#39;m trying to implement the `Table with expandable rows` from https://material.angular.io/components/table/examples but I get this error:

`There can only be one default row without a when predicate function.`

This error comes from the fact that I have two ` &lt;tr mat-row ...`, both without a when predicate (as per example). If I remove one, then the error disappears.

From my own investigation I&#39;ve found that this feature is new to Material. I upgraded to @angular/material@latest and @angular/cdk@latest and I still got the error.

**Does anyone know what I have to do to implement the table as in the example from documentation? https://material.angular.io/components/table/examples**

My versions:

    Angular CLI: 6.0.8
    Node: 8.11.2
    OS: win32 x64
    Angular: 6.0.4
    ... animations, common, compiler, compiler-cli, core, forms
    ... http, language-service, platform-browser
    ... platform-browser-dynamic, router
    
    Package                           Version
    -----------------------------------------------------------
    @angular-devkit/architect         0.6.8
    @angular-devkit/build-angular     0.6.8
    @angular-devkit/build-optimizer   0.6.8
    @angular-devkit/core              0.6.8
    @angular-devkit/schematics        0.6.8
    @angular/cdk                      6.3.1
    @angular/cli                      6.0.8
    @angular/flex-layout              6.0.0-beta.16
    @angular/material                 6.3.1
    @ngtools/webpack                  6.0.8
    @schematics/angular               0.6.8
    @schematics/update                0.6.8
    rxjs                              6.2.0
    typescript                        2.7.2
    webpack                           4.8.3



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Angular6 Material6 Error: "There can only be one default row without a when predicate function."