Error with tooltip readcomponent and subgrid

[alvisemion]

Describe the bug
Standard readcomponent raise error when showing tooltip after open a subgrid and tooltiped a column.

To Reproduce
Steps to reproduce the behavior:

1. Setup a crud with a subgrid
2. View a row with standard read component
3. Tooltip on main record; tooltip appear correctly
4. View a subgrid row
5. Tooltip on subgrid row; tooltip appear correctly
6. Tooltip back on main record; now blazor raise an error.

Screenshots

1. Tooltip ok;
   
2. subgrid tooltip ok:
   
3. Back to master, tooltip ko
   
4. Trace
   

Desktop (please complete the following information):

• OS: Windows 10
• Browser: Google Chrome
• Version 1.6.7

[gustavnavar]

Package version 1.6.8 fix this issue

[alvisemion]

Works great!