Bugzilla

**Affected versions**
* 71.0a1 (2019-09-29) 

**Affected platforms**
* Windows 10

**Steps to reproduce**
devtools.netmonitor.features.requestBlocking set on true
1. Launch Firefox, access any webpage, open the DevTools inspector - Network tab;
2. Block any request so that the Blocking UI is enabled;
3. Add at least 2 filters in the Request Blocking section;
4. Hover over the X button for any filter;
5. Click and hold the mouse button dragging the mouse over another one;
6. Release the mouse button.

**Expected result**
* x button for first filter is not displayed anymore;

**Actual result**
* both x buttons are displayed;
* first x button is displayed until another click is issued.

**Regression range**
* not a regression, only visible after implementation of bug 1580728;

**Additional notes**
* attached screenshot with the issue;

**Affected versions**
* 71.0a1 (2019-09-29) 

**Affected platforms**
* Windows 10

**Steps to reproduce**
devtools.netmonitor.features.requestBlocking set on true
1. Launch Firefox, access any webpage, open the DevTools inspector - Network tab;
2. Block any request so that the Blocking UI is enabled;
3. Add at least 2 filters in the Request Blocking section;
4. Hover over the X button for any filter;
5. Click and hold the mouse button dragging the mouse over another one;
6. Release the mouse button.

**Expected result**
* x button for first filter is not displayed anymore;

**Actual result**
* both x buttons are displayed;
* first x button is displayed until another click is issued.

**Regression range**
* not a regression, only visible after implementation of bug 1580728;

**Additional notes**
* attached screenshot with the issue;
* same issue if dragging from the filter/pattern text;