Exception when moving beetween windows in Rider

[Former user]

I have a badly formed pascall file { Avaerage out a series of numbers }

var sum, number, current; begin sum := 0; { sum of all non-zero values read so far } number := 0; { number of values read } current := read;

while current <> 0 do
begin
    sum := sum + current;
    number := number + 1;
    current := read
end;

write(number);
write(sum);

if number <> 0 then 
    write(sum / number); { the average valiue }

end.

When i swap between it and a fil written in C# i get the following

com.intellij.openapi.project.IndexNotReadyException: Please change caller according to com.intellij.openapi.project.IndexNotReadyException documentation at com.intellij.openapi.project.IndexNotReadyException.create(IndexNotReadyException.java:67) at com.intellij.util.indexing.FileBasedIndexImpl.handleDumbMode(FileBasedIndexImpl.java:821) at com.intellij.util.indexing.FileBasedIndexImpl.ensureUpToDate(FileBasedIndexImpl.java:773) at com.intellij.psi.stubs.StubIndexImpl.getContainingIds(StubIndexImpl.java:501) at com.intellij.psi.stubs.StubIndexImpl.processElements(StubIndexImpl.java:305) at com.intellij.psi.stubs.StubIndex.processElements(StubIndex.java:51) at com.siberika.idea.pascal.PascalFileIconProvider.getIcon(PascalFileIconProvider.java:30) at com.intellij.util.IconUtil.getProvidersIcon(IconUtil.java:222) at com.intellij.util.IconUtil.computeFileIcon(IconUtil.java:155) at com.intellij.openapi.fileEditor.impl.EditorsSplitters.lambda$updateFileIconAsynchronously$7(EditorsSplitters.java:430) at com.intellij.openapi.application.impl.NonBlockingReadActionImpl$Submission.insideReadAction(NonBlockingReadActionImpl.java:521) at com.intellij.openapi.application.impl.NonBlockingReadActionImpl$Submission.lambda$attemptComputation$3(NonBlockingReadActionImpl.java:486) at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1078) at com.intellij.openapi.progress.util.ProgressIndicatorUtils.lambda$runInReadActionWithWriteActionPriority$0(ProgressIndicatorUtils.java:78) at com.intellij.openapi.progress.util.ProgressIndicatorUtils.runActionAndCancelBeforeWrite(ProgressIndicatorUtils.java:161) at com.intellij.openapi.progress.util.ProgressIndicatorUtils.lambda$runWithWriteActionPriority$1(ProgressIndicatorUtils.java:118) at com.intellij.openapi.progress.ProgressManager.lambda$runProcess$0(ProgressManager.java:57) at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess$2(CoreProgressManager.java:183) at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:705) at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:647) at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:63) at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:170) at com.intellij.openapi.progress.ProgressManager.runProcess(ProgressManager.java:57) at com.intellij.openapi.progress.util.ProgressIndicatorUtils.runWithWriteActionPriority(ProgressIndicatorUtils.java:115) at com.intellij.openapi.progress.util.ProgressIndicatorUtils.runInReadActionWithWriteActionPriority(ProgressIndicatorUtils.java:78) at com.intellij.openapi.application.impl.NonBlockingReadActionImpl$Submission.attemptComputation(NonBlockingReadActionImpl.java:486) at com.intellij.openapi.application.impl.NonBlockingReadActionImpl$Submission.lambda$transferToBgThread$1(NonBlockingReadActionImpl.java:407) at com.intellij.codeWithMe.ClientId$Companion$decorateRunnable$1.run(ClientId.kt:194) at com.intellij.util.concurrency.BoundedTaskExecutor.doRun(BoundedTaskExecutor.java:216) at com.intellij.util.concurrency.BoundedTaskExecutor.access$200(BoundedTaskExecutor.java:27) at com.intellij.util.concurrency.BoundedTaskExecutor$1.execute(BoundedTaskExecutor.java:195) at com.intellij.util.concurrency.BoundedTaskExecutor$1.run(BoundedTaskExecutor.java:187) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:668) at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:665) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1.run(Executors.java:665) at java.base/java.lang.Thread.run(Thread.java:829)